Since 1985, the number of primary and secondary (P&S) syphilis cases reported in the United States has been increasing. In 1990, 50,223 cases were reported, a 9% increase from 1989. The incidence of 20 cases per 100,000 persons, a 75% increase from 1985, is the highest since 1949. This report summarizes the incidence of P&S syphilis during 1990 and provides comparison data from 1981-1990.