This section lists early pieces by Xenakis that were not published during his lifetime and works that were withdrawn from the catalog by the composer himself for various reasons.
- Untitled piece for piano (February 1949, revised in June)
- Untitled piece for piano (March 1949)
- Untitled piece for piano (27 May 1949)
- Untitled piece for piano (October 1949)
- Menuet, for piano
- Air populaire, for piano
- Allegro molto, for piano
- Untitled piece for piano (January 1950)
- Mélodie, for piano
- Untitled piece for piano (April 1950)
- Untitled piece for piano (15 June 1950)
- Andante, for piano
- Thème et conséquences, for piano (1951, unpublished)
- Dhipli zyia, for violin and cello (1951, unpublished)
- Tripli zyia, for flute, voice and piano (1952, unpublished)
- Trois poèmes, for voice and piano (1952, unpublished)
- La colombe de la paix, for alto soloist and SATB chorus (1953, unpublished)
- Stamatis Katotakis, for soloist and male voices (1953, unpublished)
- Vasarely, tape (1960, film score, withdrawn)
- Formes rouges, tape (1961, film score, withdrawn)
- Amorsima-Morsima (1956–62, withdrawn)
- GENDY301, tape (1991, withdrawn)
- Erod, tape (1997, withdrawn, created using UPIC in collaboration with Brigitte Robindoré)