The Morton Feldman Collection of Audio Recordings contains 52 reel to reel tapes and 35 cassette recordings, including performances of 38 compositions by Morton Feldman. The collection also includes some events, including the conversations between John Cage and Feldman recorded in 1966 as Radio Happenings I and II, the memorial service for Feldman at St. Mark's Church in New York City, a tribute radio program broadcast by WNYC 7 November 1987 in New York City, and an interview of Jan Williams by Sebastian Claren about Feldman. Other composers represented by recordings include Harrison Birtwistle, Pierre Boulez, John Cage, Barbara Monk Feldman, and Bunita Marcus.

The collection contains 172 original reel to reel tape recordings of 113 recitals containing approximately 613 works. The works range from the Renaissance to music created for the concerts, even improvised at the events. The reels are accompanied by audio cassette recordings created as service copies and a hard drive containing digitally reformatted preservation and access files.

The collection contains recordings of 93 of the approximately 173 concerts presented at the Evenings for New Music concerts from 1964-1980. Approximately 464 works were recorded as well as some spoken introductions to works by their respective composers. The original recordings were made on reel-to-reel tapes. The contents were transferred to cassettes in the 1980s and then digitally reformatted in 2007 onto CDs (service and in-house masters) and DVDs (preservation masters).

The collection consists of personal and research papers belonging to Renée Levine Packer, including correspondence and files for her books: This life of sounds and Gay Guerrilla. It also includes recordings of interviews conducted by Levine-Packer for her book research as well as inscribed books and commercial recordings.