At a clinic for treatment of sexually transmitted diseases, 1,453 patients were examined for pharyngeal colonization with Neisseria gonorrhoeae. A history of oral sex was reported by 895 (61.2%) of the patients. N. gonorrhoeae was isolated from the pharynges of 42 (2.9%) of the 1,453 patients. Twenty-seven of the 42 patients with N. gonorrhoeae-positive cultures gave histories of oral sex, and all 42 patients reported orogenital contact when questioned again at a follow-up visit. Seven patients with positive cultures had pharyngeal symptoms; all seven practiced fellatio. Eleven of the infected men were asymptomatic heterosexuals whose only orogenital contact was cunnilingus.