Altogether 94 patients with perirectal abscesses and/or fistulae in ano were tested for lymphogranuloma venereum in a Washington, D.C., clinic. They included men and women of low socio-economic status, many of the men being overt psycho-sexual hermaphrodites. The findings were compared with those in a control group of similar sex distribution (females, male homosexuals, male heterosexuals). All persons in the study were tested for lymphogranuloma venereum by the complement-fixation and Frei tests. Homosexuals and persons with rectal lesions were also examined by proctoscopy.Among other findings, a significantly higher frequency of Frei reactors or positive complement-fixation reactions was observed among patients (both male and female) with abscesses than among the controls and among male homosexuals than heterosexuals.The author concludes that lymphogranuloma venereum should be excluded in the differential diagnosis of perirectal abscess and fistual in ano, that homosexuals should be routinely tested for lymphogranuloma venereum, and that sexual perversion should be considered in male patients with ano-rectal disease of lymphogranuloma venereum origin.