This paper reported the results of a series of concurrent investigations in Baltimore dealing with the prevalence rates for various psychiatric disorders in the white and nonwhite population. The findings based on a community survey, and state, private and V.A. hospital rates indicate that the white population has the higher rates for the psychoses, psychoneuroses, and the psychophysiologic-autonomic-visceral disorders. Nonwhite rates are higher for the acute brain syndromes and for mental deficiency. An attempt is made to explain these variations and to refute the conclusions of a previous study by Wilson and Lantz in Virginia.