The serologic testing algorithm for recent human immunodeficiency virus (HIV) seroconversion (STARHS) distinguishes between recent acquisition of HIV infection (seroconversion, on average, in the past 129 days) or long-standing infection. STARHS was offered to sexually transmitted disease clinic patients to estimate HIV incidence and determine correlates of recent infection from October 1998 through December 1999. Of the 5227 patients tested, 116 (2.1%) were HIV infected, and 28 had recent infections. The incidence was highest among homosexual men (5.3%/year; 95% confidence interval [CI], 2.6%-10.0%), those who had HIV-infected partners (8.6%/year; 95% CI, 2.9%-21.1%), and those who had gonorrhea (6.7%/year; 95% CI, 1.5%-20.3%). Among homosexual men, African American (odds ratio [OR], 3.61; 95% CI, 1.13-11.55) or Latino (OR, 3.08; 95% CI, 1.11-8.55) race/ethnicity, and having unprotected anal intercourse (OR, 2.98; 95% CL, 1.20-7.45) or gonorrhea (OR, 3.03 95% CI, 1.07-8.63) predicted the predominance of a recent seroconversion. HIV infections in San Francisco may be shifting from white men who have sex with men to men of color who have sex with men.