The Centers for Disease Control (CDC) recommends sexually transmitted disease (STD) screening among HIV-infected persons in order to reduce HIV transmission. We evaluated the results of routine screening for syphilis and for urogenital, pharyngeal, and rectal gonorrhea (GC) and chlamydia (CT) among asymptomatic HIV-infected patients at an HIV primary care clinic in San Francisco, California. We found 15 new syphilis infections of 814 tested (1.8%) and 60 new cases of CT or GC infection of 586 tested (10.2%), with 88% of GC and CT infections occurring at nonurethral sites. Our study reveals a high rate of asymptomatic STDs among HIV-infected patients in primary care and supports the CDC recommendations to screen HIV-infected patients for STDs at all relevant anatomic sites.