To assess the prevalence of asymptomatic urethral gonorrhea and chlamydia men who have sex with men (MSM) living in greater Boston, 206 men attending routine medical appointments consented to urine-based chlamydia and gonorrhea screening using urine LCR amplification. Of those screened, 201 patients also completed a seven-question survey to assess sexual risk behaviors associated with urethral sexually transmitted infections. Less than 1% of the asymptomatic patients screened tested positive for urethral chlamydia; none tested positive for urethral gonorrhea. Forty-eight percent reported multiple sexual partners in the 30 days prior to screening, with HIV-infected patients reporting fewer partners and less unprotected insertive anal sex than HIV-uninfected patients. Almost 25% of patients screened used the Internet in the 30 days prior to screening to find a sexual partner. Internet use was associated with increased numbers of sexual partners in the 30 days prior to screening. Findings suggest that asymptomatic urethral chlamydia and gonorrhea may be uncommon in MSM living in the greater Boston area and that the recent rise in the prevalence of sexually transmitted infections may not be due to untreated asymptomatic infections. Increased awareness of STD symptoms among patients and medical providers is critical to timely diagnosis and treatment of STDs in MSM.