Secret Room

Secret Rooms are rooms that are not normally visible on the map and are usually accessed by bombing a wall leading to them. Regular Secret Rooms are usually located next to 2 to 4 rooms, while Super Secret Rooms can only be next to one room; they are placed on one of the dead ends generated on the map, similar to other Special Rooms. Very rarely, the regular Secret Room may also be located next to only one room. Entrances to Secret Rooms will never have rocks or gaps in the way. Secret Rooms usually contain at least one Shopkeeper. Secret Rooms stay open after bombing them.

Variations[]

The following room maps were made using Basement Renovator^[1] for cleaner viewing; note that all Urns you see will be Mushrooms when encountered in-game.

Possible Layouts[]

ID	Weight	Contents
0	1.0	1 Shopkeeper, 2 Fire Places, and 1 Secret Room item.
1	1.0	1 Shopkeeper, 2 Fire Places, and 3 random Coins.
2	1.0	1 Shopkeeper, 2 Fire Places, 4 Rocks and 6 random Coins.
3	1.0	1 Shopkeeper, 2 Fire Places, 4 Rocks, and 9 random Coins.
4	1.0	1 Shopkeeper, 4 Rocks, and 1 Slot Machine.
5	1.0	1 Shopkeeper, 5 Mushrooms, 4 Cobwebs, and 3 random Pickups.
6	1.0	1 Shopkeeper, 2 TNT, 4 Rocks, and 1 Chest.
7	1.0	1 Shopkeeper, 2 Mushrooms, and 3 random Pills.
8	1.0	1 Shopkeeper surrounded by 4 Cobwebs, and 3 random Coins.
9	1.0	1 Shopkeeper, 2 Fire Places, 4 Rocks in each corner, and 3 random Bomb pickups.
10	1.0 0.75	1 Shopkeeper, 2 Fire Places, 2 Red Fire Places, and a Lil' Battery.
11	1.0	1 Shopkeeper, and 2 random Key pickups.
12	1.0	4 Shopkeepers, 1 Red Fire Place, and 2 random Bomb pickups.
13	1.0	1 Key Master, 2 Mushrooms, and 1 random Key pickup. This is the only Secret Room that doesn't have a Shopkeeper.
14	1.0 0.5	3 Shopkeepers, and 1 Golden Poop.
15	1.0	1 Shopkeeper, 20 Mushrooms, and 1 Double Bomb.
16	1.0 0.25	1 Shopkeeper, 2 Fire Places, and 1 Corny Poop.
17	1.0 0.25	1 Shopkeeper, 2 Fire Places, 2 Rocks, and 2 Reward Plates.
18	1.0	1 Shopkeeper, 2 Fire Places, 20 Cobwebs, 4 Spiders, and 4 random pickups.
19	1.0 0.5	2 Shopkeepers in the upper 2 corners, with 4 more plus a Secret Room item on the other side of several gap in the floor. There are four obstacles that have equal, independent chances of being Blocks, Fire Places, Rocks, and/or Spikes; if they are Rocks, they can be bombed to bridge the gap and allow access to the room's center.
20	1.0 0.25	1 Shopkeeper, 2 Fire Places, and 1 Reward Plate.
21	1.0	1 Shopkeeper, 2 Fire Places, and several Rocks and Key Blocks blocking access to 2 rewards in the upper corners. The rewards have equal, independent chances of being Chests, Locked Chests, Grab Bags, Secret Room items, and/or random pickups.
22	1.0	3 Shopkeepers, 2 Fire Places, and 1 Nickel.
23	1.0	1 Shopkeeper, 2 Fire Places, 1 Grab Bag, and 1 Shop Restock Machine.
24	1.0 0.25	1 Shopkeeper, 2 Blocks, and 10 Mushrooms.
25	1.0 0.5	1 Shopkeeper, 2 Fire Places, and 2 Grab Bags.
26	1.0 0.5	1 Shopkeeper, 2 Fire Places, 2 Poops, 6 Mushrooms, and 1 Troll Bomb which will blow up 3 of the Mushrooms and the Shopkeeper.
27	1.0 0.25	1 Shopkeeper, 2 Fire Places, and 2 Reward Plates.
28	0.1	1 Shopkeeper, 2 Fire Places, 2 Chests, 1 Poop surrounded by 3 Flies, and 1 Secret Room item.
29	0.1	5 Shopkeepers, and 1 Secret Room item behind 4 Blocks and 4 Purple Fire Places.
30	0.1	1 Shopkeeper, 2 Fire Places, 2 Poops, and 1 Mega Battery.
31	0.25	1 Shopkeeper, 4 Fire Places, 44 Rocks, and 1 Rainbow Poop.
32	1	1 Shopkeeper, 2 Poops, 10 Mushrooms, and 5 random Coins.
33	0.5	2 Shopkeeper, 4 Fire Places, 2 Rocks, and 4 Spiked Rocks which surround 1 random Card.
34	0.5	1 Shopkeeper, 2 Fire Places, 4 Mushrooms, and 1 Secret Room item surrounded by 4 Spikes cardinally and 4 Spiked Rocks diagonally.
35	1	1 Shopkeeper, 3 random Coins, along with 1 Chest and 1 Locked Chest each in the upper corners that are both blocked by 2 Spiked Rocks.
36	1	2 Shopkeepers, 1 Spiked Rock in each corner, and 1 random Chest that is surrounded by Rocks, which can be destroyed with 1 nearby TNT which is itself behind Spikes on each side.
37	0.5	One Rotten Beggar, 4 Mushrooms, and 3 random Coins.
38	0.5	1 Shopkeeper, 2 Fire Places, 1 Block in each corner, and 1 Wooden Chest.

Starting from the second floor of Chapter 2 onward, Greed and Super Greed have a chance to replace Secret Rooms.

Alternate Variations[]

Secret Rooms in alternate chapters ( Downpour, Dross, Mines, Ashpit, Mausoleum, Gehenna and Corpse) differ from the standard layouts. Each alternate floor has 11 unique layouts (12 in Downpour). Regular Secret Room layouts cannot appear on these floors.

Super Secret Rooms[]

Super Secret Rooms are only located next to one other room, and this room can't be a Special Room; in other words, it is placed on one of the floor's dead ends, like any other Special Room. Each Super Secret Room has set drops depending on the floor. Note that the type of Super Secret Room is not limited to certain floors it mimics (e.g. Isaac can find a Womb-themed Super Secret Room in Depths).

Super Secret Rooms are most likely to be found either at the end of a series of rooms that lead to a dead-end, and is particularly likely to appear near the Boss Room, as they are the second room type to be placed on a map during Map Generation, and are therefore placed far away from the room Isaac starts in.

Possible Layouts[]

ID	Weight	Room theme	Contents
0	1	Womb	8 random Red Hearts. Only Red Hearts can be created in this room, regardless of what item is used to create said Hearts (e.g. V - The Hierophant will create 2 Red Hearts rather than Soul Hearts).
1	1	Cathedral	1 Eternal Heart. Only Eternal Hearts can be created in this room, regardless of what item is used to create said Hearts (e.g. V - The Hierophant will drop 2 Eternal Hearts rather than Soul Hearts).
2	1	Sheol	1 Red Chest.
3	1	Necropolis	1 Fortune Telling Machine.
4	1	Cellar	1 random trinket.
5	1	Basement	5 random Pills.
6	0.5	Library	1 Black Heart. Only Black Hearts can be created in this room, regardless of what item is used to create said Hearts (e.g. V - The Hierophant will drop 2 Black Hearts rather than Soul Hearts).
7	0.1	Dark Room	1 Black Heart.
7	0.1	Dark Room	1 Nulls in each corner, and 5 random Pills/Runes.
8	0.5	Burning Basement	1 Shopkeeper, 2 Bomb Chests, 3 TNT, 13 Fire Places, and 5 Red Fire Places. All Fire Places in the room will be extinguished if this room appears in Downpour or Dross.
9	0.1	Flooded Caves	1 Black Poop surrounded by 6 retracting Spikes.
10	0.5	I AM ERROR room	Can contain any of the following: Mom's Hand, Rag Man, random pickups, Chests, Cards, trinkets, Pills, and/or items.
11	1	Womb	4 Red Poops, and 3 Double Hearts.
12	0.1	Cathedral	3 Soul Hearts, 2 Blue Fire Places, and an Angel Statue which will summon an Angel if blown up, who will then drop a Key Piece upon death.
13	0.1	Sheol	3 Black Hearts, and 2 Black Globin's Heads.
14	1	Shop	1 Beggar, and 1 Blood Donation Machine.
15	0.1	Womb	1 Red Poop surrounded by 3 Flies, and a random number of various types Red Hearts, except Double Hearts.
16	0.1	Cathedral	1 Rainbow Poop surrounded by 3 Flies, and 2 Eternal Hearts.
17	0.1	Sheol	1 Black Poop surrounded by 3 Flies, and 6 Red Chests.
18	0.1	Shop	2 Fortune Telling Machines and 3 Slot Machines.
19	0.1	Basement	1 Red Poop surrounded by 3 Flies, and 9 random Pills.
20	0.5	Library	1 Battery Bum, 4 Urns, 2 Cobwebs, and 3 random Coins.
21	0.5	Burning Basement	1 Bomb Bum, 3 Rocks and 3 Fire Places in each corner, and 4 random Bomb pickups.
22	0.25	Basement	1 Shopkeeper, and 4 Greed Gapers.
23	0.5	Corpse	1 Spiked Rock in each corner, and 3 Rotten Hearts.
24	0.5	Arcade	5 Micro Batteries. The middle one has a 50% chance to be a Lil' Battery.
25	0.25	Dank Depths	1 pickup which has an 83% chance to be a Golden Key and a 17% chance to be a Golden Bomb, surrounded diagonally by 4 Skulls.
26	0.01	Ashpit	8 Urns, and 1 lit Giga Bomb that explodes shortly after.
27	1	Corpse	1 Rotten Beggar, and 1 Blood Donation Machine.
28	0.5	Mausoleum	3 Urns in each corner, and 2 Black Sacks.
29	0.25	Gehenna	4 Spikes, and 1 Golden Battery.
30	0.25	Chest	1 Mega Chest, and 2 random Key pickups.
31	0.5	Cellar	4 Rocks, and 2 Wooden Chests.
32	1	Cathedral	1 Confessional.

Greed Mode Layouts[]

Greed Mode has its own set of Super Secret Room layouts.

ID	Weight	Room theme	Contents
0	1	Womb	5 Red Hearts. Only Red Hearts can be created in this room, regardless of what item is used to create said Hearts (e.g. V - The Hierophant will create 2 Red Hearts rather than Soul Hearts).
1	1	Arcade	5 Pennies.
2	1	Catacombs	3 Keys.
3	1	Burning Basement	3 Bombs.
4	1	Cathedral	2 Soul Hearts. Only Soul Hearts can be created in this room, regardless of what item is used to create said Hearts (e.g. VI - The Lovers will create 2 Soul Hearts rather than Red Hearts).
5	1	Library	1 Black Heart. Only Black Hearts can be created in this room, regardless of what item is used to create said Hearts (e.g. V - The Hierophant will create 2 Black Hearts rather than Soul Hearts).
6	1	Chest	1 Chest; small chance to spawn another type of Chest instead.
7	1	Chest	1 Bomb Chest.
8	1	Sheol	1 Red Chest.
8	1	Sheol	2 Red Chests.
9	1	Basement	4 random Pills.
10	1	Library	2 random Cards.
11	1	Cellar	4 Lil' Batteries. Each battery has a 50% chance to be a Micro Battery instead.
12	1	Dark Room	2 random Runes.
13	0.5	Sheol	2 Red Chests.
13	0.5	Sheol	3 Red Chests.
14	1	Cellar	2 random trinkets.
15	0.5	Cellar	1 random trinket.
16	1	Clean Bedroom	1 bed.
17	1	I AM ERROR room	1 trapdoor to the next floor.
18	0.5	Basement	17 Poops.
19	0.25	The Shop	1 Golden Bomb.
20	0.5	The Shop	1 Golden Poop.
21	0.25	The Shop	1 Golden Key.
22	1	Secret Room	1 Greed Mode Treasure Room item. 1 Greed Mode Secret Room item.
23	1	Chest	2 Locked Chests.
24	1	Cathedral	1 Eternal Heart. Only Eternal Hearts can be created in this room, regardless of what item is used to create said Hearts (e.g. V - The Hierophant will create 2 Eternal Hearts rather than Soul Hearts).
25	1	Womb	1 Half Red Heart. Only Half Red Hearts can be created in this room, regardless of what item is used to create said Hearts (e.g. V - The Hierophant will create 2 Half Red Hearts rather than Soul Hearts).
26	0.1	Arcade	1 Golden Penny.
27	0.5	Necropolis	1 Greed Mode Secret Room item surrounded by pits and 2 spike rocks that can fill up pits when destroyed from a certain direction.

Ultra Secret Rooms[]

Ultra Secret Rooms are special rooms that are not connected to any other room on the map directly. They are not revealed by most mapping effects ( The Mind, etc.) and can only be revealed on the map with Cracked Orb, Book of Secrets wisps, and Rune Shard. They can be accessed directly by opening Red Rooms adjacent to them using Red Key or Red Key wisps, Crystal Key, Cracked Key, and Soul of Cain: entering a Red Room next to the Ultra Secret room will reveal its position and automatically open the doorway leading into it. It can also be entered by teleporting to it using XVIII - The Moon?; when teleported into, a pathway of Red Rooms back to the rest of the level will be opened automatically. Ultra Secret rooms contain items from the Ultra Secret Room item pool.

Ultra Secret rooms are most likely generated in spots that connect to the highest number of non-red rooms through its adjacent red rooms (different squares in L rooms count as 2). There is about a 20% chance that it will select the next most likely spot and another 20% for the one after and so on. Which means it has about an 80% chance to select the 1st spot, 16% chance for the 2nd, 3% for the 3rd and less than 1% for the 4th.

Ultra Secret Rooms can't be connected to Secret Rooms or Super Secret Rooms (as of 1.7.5), and can't be in a location where any of its adjacent red rooms are invalid, such as next to a Boss Room (Boss Rooms in The Void can have red rooms next to them, but the Ultra Secret Room will never be connected to one), next to the sides of narrow rooms, or any room that can't have a red room opened on that specific side, however locations on the 13x13 border where a red room would normally open to an I AM ERROR room are allowed.

ID	Weight	Room theme	Contents	Image preview
0	1		A map without an USR

Notes[]

Generally, the best strategy for finding Ultra Secret Rooms is by checking the location that connects to the highest number of non-red rooms, and if it's not there, checking the spot with the next highest number.
If the only remaining valid locations are connected to a single non-red room, it's just as likely for the Ultra Secret Room to be connected to the side of a single room as it is connected to a corner.
The doors of the Ultra Secret Room are opened automatically only when approached from the outside. If other rooms exist adjacent to it, the doors will not open from inside the Ultra Secret Room without bombing them or returning from the outside.
- Red Key or Cracked Keys must be used before the bombs, as otherwise explosions won't have an effect.
In the Mirrored World, the Ultra Secret Room will be empty, same as any Special Room.
It's possible for the Ultra Secret Room to not generate if there are no valid locations.

Layouts[]

ID	Weight	Contents
0	?	2 Shopkeepers, 4 Poops behind Key Blocks, some Cobwebs, 2 random Keys, and 1 Ultra Secret Room item.
1	?	Several Key Blocks and Metal Blocks along the walls, and 1 Ultra Secret Room item.
2	?	2 Shopkeepers, several Key Blocks, and 1 Ultra Secret Room item.
3	?	1 Shopkeeper behind Key Blocks, a few Cobwebs, and 1 Ultra Secret Room item blocked off by Key Blocks and Metal Blocks.
4	?	1 Shopkeeper, a few Cobwebs, and Rocks in the shape of a Key, with 1 Ultra Secret Room item inside the Key's 'loop'.
5	?	2 Shopkeepers, a few Cobwebs, several Urns, 3 random Coins, and 4 Greed Gapers guarding 1 Ultra Secret Room item.
6	?	10 Shopkeepers, 2 Fire Places, a Rock, some Cobwebs, and 2 Ultra Secret Room item.
7	?	2 Shopkeepers, some Cobwebs, a Rock, 10 Keys, and 2 Key Rings.

Notes[]

Secret Rooms are found by bombing the middle of a wall in a standard size room. For larger size rooms, divide the room mentally into the size of individual rooms to figure out where to bomb. For closet-size rooms, Secret Rooms will never be found by bombing the sides but may be found by bombing the wall at the end of the closet.
Rooms adjacent to Secret Rooms will always have a clear, walkable path to the middle of the wall where Isaac can place a bomb. Secret Room entrances are never found in front of gaps, obstacles, or spikes. Each rooms adjacent to a Secret Room must satisfy these requirements, so if one room near a suspicious gap in the map fails these requirements, then look elsewhere.
If there are no valid Secret Room locations surrounded by 3 or 4 rooms, it is possible for a Secret Room to be adjacent to only 1 or 2 rooms.

X-Ray Vision opens all available entrances to both the Secret Room and the Super Secret Room. The I Can See Forever pill does the same for the floor on which the pill was used. Dog Tooth will play a howl sound effect when Isaac enters a room adjacent to a Secret Room or Super Secret Room, and YO LISTEN! will hover over Secret Room entrances.
Teleportation items can randomly teleport Isaac into Secret Rooms, and XVIII - The Moon will always teleport Isaac to the Secret Room.
Secret Rooms are revealed on the map with Blue Map, Book of Secrets, Crystal Ball, The Mind, Spelunker Hat, XIX - The Sun, or XXI - The World, but Isaac will still need to open their entrance.
Red Key can be used to find Secret Rooms. The lack of Red door frame means a Secret Room could have generated on the other side.
Star of Bethlehem sometimes reveals Secret Rooms as it can travel through them.
If Greed or Super Greed spawn inside a Secret Room, Isaac won't be able to exit it (like a Mini-Boss Room), but once the fight ends, all the exits of the Secret Room will be accessible.
- An exception to this is that Challenge Rooms and Boss Challenge Rooms will be inaccessible; the metal bars won't be removed from walls that lead to them after the fight concludes.
Secret Rooms can exist next to all types of rooms except Boss Rooms, allowing certain restricted rooms to be entered.
- Even if Isaac has no Keys, it is possible to bomb into a locked Special Room should there exist an adjacent Secret Room. Leaving through the door will unlock the room without requiring a Key.
- It is possible to enter Curse Rooms without taking damage by bombing in from a Secret Room.
- It is possible to access Challenge Rooms even if Isaac doesn't meet the health requirements, but it is not possible to "steal" the items, as the hole will be blocked up as soon as the fighting stage begins.
Secret Rooms of all types do not exist in the Ascent.
Once Corrupted Data is achieved (beating Delirium as Tainted Eden), items that spawn Secret Rooms room have a chance to be randomized as if affected by TMTRAINER.
Super Secret Rooms replace the dead-end room that would require the 2nd most rooms walked through from the start room to access, and cannot be connected to the Secret Room.
- For reference, the Boss Room takes the dead-end room that would require the most rooms walked through, and the Shop takes the room that would require the 3rd most. This means that the Super Secret Room is equally as far or further from the start room than the Shop. It also means the Super Secret Room tends to be close to the Boss Room. Loops and large rooms connected to more than one room on any given side can tamper with this logic, however.
Super Secret Rooms can have layouts from floors that Isaac hasn't unlocked yet.

Trivia[]

In the original The Binding of Isaac, Secret Rooms worked differently; if the player left a room after opening a Secret Room entrance, the entrance would disappear. To access the room again for any purpose, the player needed another Bomb to reopen the entrance.
Prior to V1.7.5, Ultra Secret Rooms used the Angel Room Item Pool. This was meant as a placeholder.

Seeds[]

PC 927Q 481S (Secret Room above Treasure Room is not attached to any others)

PC 2CC7 S7YG (Secret Room is attached to only one room; located on the eastern wall in the most eastern room starting from the spawn room)

PC 419H 1DQM (Take the Red Key in the Curse Room left of the starting room, then use it on the right-hand wall of the Curse Room to reveal a Red Room which opens the Ultra Secret Room)

Bugs[]

Bug!	After defeating an Angel spawned in a Super Secret Room, the music will not return to the floor's regular music.

Bug!	Teleporting to the Super Secret Room in Greed or Greedier Mode, when the room is generated behind a still-locked Treasure Room, can trap Isaac inside.

Bug!	Certain secret rooms result in a crash (observed on seed THWM 9284, Dank Depths II)

Bug!	If the Ultra Secret Room only connects to curse rooms, being teleported to it will result in no doors opening, resulting in a softlock. This likely happens because the game only tries to open doors that don't force you to go through the curse room, but since it's the only path, no doors open.