Since 1932 there has been carried on a study of the outcome of untreated syphilis in the male Negro.*Although the primary objective of this study is the determination of the clinical outcome, this group of patients also furnishes valuable data on the serologic pattern of untreated syphilis. No serologic data are available for the period from the initial examination in 1932-1933 to the first follow-up examination in 1938-1939. Since 1939, however, annual serologic examinations have been attempted. The last examination, completed in December, 1954, extended the observation period to 22 years. The initial serologic examination in 1932-1933 was based on the Kolmer complement fixation and Kahn standard flocculation tests for syphilis, performed at the National Institute of Health. For the 1938-1939 and subsequent surveys serologic testing has been done by the Venereal Disease Research Laboratory (formerly at Staten Island, N. Y., and now located at