We surveyed 454 men in November 1983 and in May 1984 regarding their sexual practices during the month before the survey. In the 1983 survey, we also asked for reports about sexual behavior during the same month 1 year prior to the survey. The sample consisted of men recruited as they left bath-houses and bars, men who had not used bars or baths for meeting sexual partners for 2 months prior to the November 1983 survey, and men in committed primary relationships with another man. We found substantial changes in reported sexual behavior with persons other than a primary partner. The average number of male partners declined from 6.3 in November 1982 to 3.9 in May 1984. Receptive anal intercourse without condom declined from 1.9 to 0.7, oral-anal contact declined from 1.1 to 0.3, and swallowing semen declined from 2.8 to 0.7 in terms of the number of times that the respondent engaged in the act in the last month. These same changes did not occur in relation to sex with a primary partner. Only one variable, namely, increased length of time since the first homosexual experience, distinguished persons maintaining few sexual partners from those increasing the number of sexual partners from November 1983 to May 1984. Four variables distinguished those retaining high numbers of sexual partners from those lowering the number of sexual partners, namely, ability to remember a visual image of AIDS deterioration, age, relationship status, and length of time since first homosexual experience.