The Black Sleep (alternate title Dr. Cadman’s Secret) a 1956 American independent horror film directed by Reginald LeBorg, and written by John C. Higgins from a story by Gerald Drayson Adams. It stars Basil Rathbone, Lon Chaney Jr., John Carradine, Bela Lugosi, and Akim Tamiroff. Tor Johnson appears in a supporting role. The film was produced by Aubrey Schenck and Howard W. Koch, as part of a four-picture finance-for-distribution arrangement with United Artists.

The film was released as a double feature with the 1955 British film The Creeping Unknown (the title of the American release of the British film The Quatermass Xperiment). The Black Sleep was re-released in 1962 under the title Dr. Cadman's Secret.