The Ethical Culture Society of Los Angeles Collection includes material produced and/or assembled by the Los Angeles Chapter of the Ethical Culture Society. The bulk of the collection consists of over 450 public addresses and newsletters presented at the weekly meetings of the Ethical Culture Society of New York and various regional chapters. It also contains periodicals, serials, and printed material produced by members from various chapters of the Ethical Culture Society and the American Ethical Union. The collection is divided into two series, Ethical Culture Society Files (1946 -1980) and American Ethical Union Files (1966-1986).

Series I, Ethical Culture Society Files, include addresses, newsletters, papers, text fragments, and printed material related to the Ethical Culture Society originating from various regional chapters. This series is divided into three subseries: Addresses and Newsletters from Regional and Unknown Chapters (1946-1980), Related Addresses and Publications (1946-1980), and Text Fragments (1960-1966). Addresses and Newsletters from Regional and Unknown Chapters is further divided into regional chapters. The material is arranged alphabetically by the name of the specific regional chapter. Within the specific regional chapter, the material is arranged alphabetically by author/presenter, and chronologically where there are multiple works by the same author/presenter. The material is arranged by title where there is no author/presenter and chronologically where there is no title and author/presenter.

Series II, American Ethical Union Files, contains materials created by the parent organization of the Ethical Culture Society, the American Ethical Union. The series includes addresses, newsletters, journal publications, magazines books. The materials are separated into two subseries: Addresses (1971-1986), and Publications (1966-1983).