Adenoviruses (Ads) are an important cause of respiratory illness, conjunctivitis, and gastroenteritis, but they are seldom recognized as a potential cause of sexually transmitted disease. We performed virus cultures on approximately 7,000 patients attending a sexually transmitted disease clinic or other health department clinics for the evaluation of genital ulcers, urethritis, or conjunctivitis. Ads were isolated from genital or conjunctival specimens obtained from 23 (0.33%) patients. Among the 20 Ad-positive men, 15 (75%) had urethritis, 12 (60%) had conjunctivitis, and 10 (50%) had both. All three Ad-positive women had vaginal discharge and genital ulcers or fissures. Ad isolates from 17 patients were available for serotyping. Ad type 37 was isolated from 14 patients, Ad type 8 was isolated from 2 patients, and Ad type 2 was isolated from 1 patient. In three of the Ad type 37 cases, Ad was recovered from both urethral and conjunctival specimens. One of the Ad type 8 cases had conjunctivitis, but the Ad type 2 case did not. Ads, particularly type 37, may be a sexually transmissible cause of genital ulcers, urethritis, and conjunctivitis.