Binding of Isaac: Rebirth Wiki
Binding of Isaac: Rebirth Wiki

Added in Repentance

Red Key is an activated item added in The Binding of Isaac: Repentance.


  • Allows Isaac to create new rooms by using the key next to a wall where there would be no conditions that could prevent a room from spawning there. This is indicated by red door outlines on walls.
  • These rooms are most commonly normal rooms, but have a 10% chance to be various special rooms instead, even including red Devil Rooms or red Angel Rooms.
    • Red special rooms of any kind can appear in every floor.



  • All rooms made by Red Key will be 1x1 rooms that can have doors available on all sides.
  • In Home Home, Isaac can create a room on the left side of the map right under Mom's room. This room contains the Tainted characters.
    • If the respective Tainted character has already been found or a Tainted character is played, the room will contain 15►Inner Child Inner Child instead. If Inner Child has not been unlocked, the room will contain a Shopkeeper.
  • If a door created by Red Key takes Isaac outside of the 13x13 area of the floor, he will be taken to the I AM ERROR room.
    • Isaac can't exit this room, forcing him to use the trapdoor unless he has a teleport.
    • This does not function in Corpse Corpse II, Chest Chest, Dark Room Dark Room, The Void The Void, or the special version of  Mausoleum Mausoleum/Gehenna Gehenna II) containing {I|{Dad's Note}}. No door outlines will appear at any boundary walls.
      • Additionally, this method also doesn't work during the Red Redemption challenge.
    • The I AM ERROR room can only be entered from another red room. Normal rooms will not show the red outline if they are at the map's boundary.
    • The I AM ERROR room will not appear on the map when created.
  • Red rooms enable Isaac to enter several special rooms on the normal map without any resources or special conditions. These include the Secret and Super Secret room, Challenge Rooms, Vaults, and Bedrooms.
  • Red Shops will regularly not offer items from the Shop item pool for sale, but instead draw from Boss and Treasure Room pools instead. Additionally, red shops have a chance to become advanced shops with many more items for sale, akin to Tainted Keeper Tainted Keeper's better shops.
  • Red Key can't overwrite Secret Rooms or Super Secret Rooms. This can be used to discern the location of secret rooms by finding walls that don't have red door outlines in a valid red room spot.
  • Red Key can't create a room adjacent to the Boss Room in most floors, with some exceptions:
    • Red Key can create a room adjacent to Hush's room in the top right where the room that leads to The Void The Void usually generates. The door to this looks like a crack.
      • This red room can only be created when Isaac is in another red room adjacent to it, i.e. from branching off one of the Treasure Rooms and going around Hush's room. Isaac cannot create it inside the boss room, even after Hush is defeated.
      • Isaac can enter Hush's room from this crack, but going the other direction will lead him to the Entrance Portal room.
    • Red Key can create rooms adjacent to boss rooms in The Void The Void, including Delirium's room.
      • Isaac can use this mechanic to find Delirium's room by creating rooms until he gets two adjacent rooms with boss doors on the same wall.
        • There's a small chance that this may be Mr. Fred instead.
    • Red Key can create rooms adjacent to the boss room in the Mirrored World of Downpour Downpour/Dross Dross II.
  • Aside from XVIII - The Moon? XVIII - The Moon?, Red Key is the most reliable way to reach Ultra Secret Rooms, which have the Home Home floor layout and are very likely to contain an Angel Room item.
    • When Isaac enters any red room adjacent to the Ultra Secret Room, it immediately appears on the map along with the Secret Room sound, and its door will automatically open.
  • If Isaac encounters a red Special Room, all of its doors will be its special theme doors.
    • All doors in a red Curse Room still feature spikes, which will damage Isaac if he decides to enter/exit.
    • A red Vault's doors or a red Dice Room's doors each require two keys to open. The door where Isaac uses Red Key will be automatically unlocked, but the other doors remain locked until Isaac goes through them from inside or unlocks them from outside.
  • Multiple red special rooms of the same type can spawn on one floor.
  • All Sacrifice Rooms made by Red Key will have their own independent use counters and rewards.
  • If Isaac has a teleport to a specific room (XVII - The Stars XVII - The Stars, IX - The Hermit IX - The Hermit, 15►Teleport 2.0 Teleport 2.0, etc.) and has created a special room such that there are multiple of a certain type on one floor, the teleport will choose randomly between each room.
    • However, if Isaac has found a red Planetarium, XVII - The Stars will always teleport Isaac to it over any Treasure Rooms.
  • It is possible to obtain Knife Pieces outside of the intended methods by spawning Treasure Rooms that contain them.
  • In Downpour Downpour II or Dross Dross II, if Isaac enters a red room after touching the white fire and becoming The Lost The Lost, he will still be The Lost in every red room, but will change back to the original character when entering a normal room.
  • Isaac is allowed to create red rooms in the mirror world of Downpour Downpour II or Dross Dross II. They will be reflections of the original floor's red rooms, and special rooms created in this way will still be empty.
  • Red rooms can't be created around the 15►Knife Piece 2 Knife Piece 2 area of Mines Mines II or Ashpit Ashpit II.
  • Red Rooms on Depths Depths I/II can contain Marked Skulls.
  • Red rooms created in Downpour Downpour or Dross Dross I/II may contain the white fire, which allows Isaac to switch into The Lost The Lost temporarily.
  • Red rooms created in Mines Mines or Ashpit Ashpit I/II may contain the special yellow buttons used to create the minecart path. These buttons have no actual effects. Even in floor II, Isaac still needs to find the three original buttons.
  • When in Chest Chest or Dark Room Dark Room, their spawn room containing their respective chests can be created by the Red Key.


  • Match Stick Match Stick will situationally make room drops less valuable.
  • 15►4.5 Volt 4.5 Volt in most cases gives less charges per room cleared as red rooms are always 1x1.
  • 15►A Pound of Flesh A Pound of Flesh will in most circumstances heavily reduce the value of shops created, making it a situational item to take with Red Key. This however does not apply to Keeper's Bargain Keeper's Bargain.
  • 15►Member Card Member Card in red Shops does not create new areas, as they connect to the shop much like Crawl Spaces.

In-game Footage[]



PCHard mode only CL9P JM0R (Eden Starting Item)

PCHard mode only B0H6 M13C (Curse Room next to spawn)

PCHard mode only 67DH 1KJ4 (Curse Room next to spawn)

PCHard mode only CC6W JJ3N (Curse Room next to spawn)


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