Results are presented from two sources, data of which indicate an increase in high-risk sexual behaviors for human immunodeficiency virus infection among homosexual men. The number of cases of gonorrhea among homosexual and bisexual visitors to municipal sexually transmitted disease clinics in Amsterdam, The Netherlands, is increasing. An increase was also observed in unprotected anogenital intercourse among homosexual participants in the Amsterdam cohort. These findings indicate that a rebound in the behavior change process among homosexual men is occurring. Furthermore, longitudinal behavioral data show that lapse and relapse into unsafe sex are prevalent in the Amsterdam cohort.