The music in The Binding of Isaac: Rebirth, Afterbirth, Afterbirth †, and Repentance was created by Ridiculon. These soundtracks can be purchased on Steam and on Ridiculon's Bandcamp page, as well as being available on Spotify, containing 32, 9, 4, and 20 tracks, respectively. Not all tracks heard in-game are included in the OST releases, and some tracks in the OST do not appear in-game or go unused.
Most main floor tracks have a heavier variant that plays when enough enemies or bosses are in the room. In the OST, these variants are generally heard in each song’s second half. What instrument is added is listed next to each track's name in square brackets.
Ridiculon have also released a single titled The Binding of Christmas, though this is only available on Bandcamp.
Devoid and The Fallen Angel's descriptions are simply a line of underscores on Bandcamp, while they have real descriptions in the Spotify release. This was likely done to prevent spoilers, as Dark Room was new to Rebirth and not present in Flash Isaac. Terminus also has these underscores, but the description is entirely absent in the Spotify release.
The Legend of Bum-Bo, a Binding of Isaac spinoff, has a title theme that sounds similar to and shares a name with Rebirth’s title theme.
In an interview on Steam, Ridiculon producer Jon Evans listed the OST songs he is most proud of: “‘Sodden Hollow’ for its dripping groove. ‘Sheol’ for even being allowed to be so terrifying in a game OST. ‘Delirium’ for its dank heaviness.” He also points out that “every track we’ve written for Repentance is our fave.”
???’s and Home’s music both have “heavy” layers that normally cannot be heard in-game since their respective floors do not contain enemies.
???’s theme can now be heard in-game by various methods, such as using Red Key in ???.
The filename of Jesus Loves Viggo alludes to Viggo Bossi, Isaac’s voice actor, who sings on the track.