- “Themes, moods and even the duration of these pieces will change and adapt with each player's Halo experience. I took the liberty of remixing and rearranging all the music in order to make listening to the soundtrack more enjoyable.”— Martin O'Donnell
Halo: Original Soundtrack is the soundtrack for the video game Halo: Combat Evolved. Composed by Martin O'Donnell and Michael Salvatori, it was released on June 11, 2002. It contains most of the music from Halo: Combat Evolved, with some pieces remixed into medley form. The soundtrack features a wide range of musical styles including chanting, string orchestra, and percussion. A special edition of the soundtrack was released on October 28, 2003, featuring a trailer, demo movie, and music for Halo 2.
- Brendan O'Brien - Producer
- Michael Ostin - Supervisor
- Mike Plotnikoff - Engineer
- Keith Armstrong - Mixing Assistant
- Eric Miller - Engineer
- Sandy Ting - Executive Producer
- Cameron Payne - Marketing
- Martin O'Donnell - Conductor, Producer, Orchestration
- Dim e - Mixing Assistant
- Nile Rodgers - Vocals, Producer, Supervisor
- Chris Lord-Alge - Mixing
- Howard Benson - Producer
- Flea - Trumpet
- Richard Hilton - Engineer
- Steve Vai - Guitar
- Many pieces from Halo 2: Original Soundtrack and Halo 3: Original Soundtrack are remixes of or are based on pieces from this soundtrack.
- While not displayed on the list of tracks, the soundtrack contains the song Siege of Madrigal. It plays following a period of silence near the end of the last track.
- One piece of music, heard on the level Assault on the Control Room, does not appear on the soundtrack. It is available on Bungie's website here. Bungie and Marty O'Donnell have never publicly named the piece, and is thus referred to as "The Lost Song" or "The Lost Muse" by fans.