According to Mitsuda, the music of Xenogears belongs to the traditional music genre. Though he first described it as stemming from "a world of [his] own imagining" rather than any specific country, he has also claimed a strong Irish or Celtic music influence. His musical approach for the original soundtrack was to insert Celtic influences into "easy-to-listen-to" pop tracks rather than making either "dense" Celtic music or simple background music.
The music of Xenogears, composed by Mitsuda, is rooted in traditional music but incorporates Celtic influences, particularly in the form of easy-to-listen-to pop tracks. This approach aims to create a unique blend of musical styles without resorting to either overly complex or simplistic arrangements.