RahXephon O.S.T. 1 is the first soundtrack album released for RahXephon. Except for the opening track, Hemisphere, all music and lyrics are by Ichiko Hashimoto and performed by her. She is joined by her sister Mayumi Hashimoto on the last track.

"Yume no Tamago (Egg of the Dream)", the last track, was used as the ending theme for all but the last episode. The musical theme from this track also appears as one of the musical themes in the ending of the last episode, "Before you know". It is also used by "Second Sorrow" in episode 19 "Blue Friend".

RahXephon O.S.T. 2 is the second soundtrack album from the anime series RahXephon. All music and lyrics are by Ichiko Hashimoto and performed by her. She is again joined by her sister Mayumi Hashimoto on the song "Yume no Tamago (Egg of the Dream)". Houko Kuwashima, the voice of Quon, also sings on this album.

Hashimoto described this as "more organic" than the first soundtrack, and it contains some music that was recorded after the series had begun airing.

The theme of "La, la Maladie du Sommeil" is from Polovetsian Dances. This track is featured on the album Junsyoku Brilliant (緋色brilliant) (VICL-61796).

The track "Huge Suites" ( sample ) features a melody played in turn by different instruments, over a snare drum rhythm and a counter-melody, beginning quietly and rising in a crescendo. This track thus shares some of its structure with Maurice Ravel's Boléro. The initial rhythmic pattern in "Huge Suites" is simpler than that in Boléro, consisting of only 6 beats. The track as a whole is more ornate, however, with transitions in melody theme and rhythmic pattern. While the main melody of Boléro transitions back and forth between two themes ([[:Media:|Theme A]] [[:Media:|Theme B]] ), this track transitions back and forth between four themes. The first rhythmic change is at 1:23, coinciding with the third theme transition. At 2:00, the string section returns to the original rhythmic pattern while the percussion does not; the previous rhythm thus becomes a counter-rhythm. In contrast, Boléro keeps the same rhythmic pattern going all the way until the end. "Huge Suites" has its final transition at 2:18, where the counter melodies end and both the rhythm and theme dive into a crescendo that builds for the last 40 seconds of the track. The main theme from this track is also used for the song "Brave" on the next album.

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