Many individuals remain sexually active into their eighth decade. Surveillance data suggest that rates of sexually transmitted infections in older patients are increasing. We compared demographics, risk behaviors, and predictors of acute infections in patients 50 years and older versus younger patients attending sexually transmitted disease clinics in Baltimore, Maryland. This was a retrospective study from a large electronic database of visits to two urban sexually transmitted disease clinics between 2005 and 2010. Proportions were compared using the Chi square test. Logistic regression was used to assess predictors of acute sexually transmitted infections in older versus younger groups. It was found that patients over 50 were more likely than younger patients to report never using condoms (32.6% [CI 0.31–0.34] versus 24.1% [CI 0.23–0.25]). The overall prevalence of acute sexually transmitted infections was 18.1% (CI 0.17–0.19) in older and 25.8% (CI 0.25–0.27) in younger patients. Older women were more likely to be diagnosed with trichomoniasis (21.5% [CI 18.6–24.5] versus 13.1% [CI 11.5–14.8]). Black race was predictive of having an acute sexually transmitted infections in younger men (OR 2.2 [CI 1.47–3.35]) and women (OR 2.7 [CI 1.34–5.30]) but not in older men (OR 1.2 [CI 0.79–1.73]) or women (OR 1.2 [CI 0.43–3.15]). Older age was associated with a decreased risk of acute STI diagnosis in younger men and older women only, while having had sex for money or drugs in the past month was predictive only in younger women. Reporting symptoms and increasing numbers of sexual partners in the last six months was predictive of acute sexually transmitted infection diagnosis in all age groups. Older patients seeking care at sexually transmitted disease clinics engage in important risk behaviors. Race, a factor predictive of acute sexually transmitted infections in younger patients is not a significant predictor of sexually transmitted infections in older persons.