An avoidance conditioning technique for homosexual men developed by us was subjected to controlled clinical testing, with long-term (two-year) follow-up. In five of eight treated patients and in none of eight placebo treated patients, homosexual response suppression was produced. Group psychotherapy was concomitantly employed to work through heterosexual fears and other blocks and problems. Indices of change included frequency measures of sexual behaviors (including dream and fantasy behaviors), psychological testing, and clinical ratings by outside psychiatrists (interrater reliability, 0.96). Conditioning treated patients were significantly more improved than placebo treated patients in terms of sexual behavior change (P = 0.001). Successfully conditioned patients reported absence or marked diminution of homosexual feelings as well as of overt homosexual behaviors. Even though booster conditioning treatments were not used, two of eight patients achieved sustained happy heterosexual adjustments.