Men (n = 83) and women (n = 86) at nine dating bars in Ontario, Canada, were surveyed to determine gender differences in self‐reported casual sex and AIDS‐prevention behavior. Data analysis focused on 169 bar patrons who had experienced sexual intercourse. More men than women had some experience with casual sex. The women had as many sexual partners as the men, but were less likely to anticipate having casual sex and reported less enjoyment and more guilt about casual sex than did the men. Almost all men and women had declined at least one opportunity to have casual sex. Women expressed greater fear of being physically harmed during a casual encounter and were more concerned about the risks of AIDS and other sexually transmitted diseases than were men. Although the respondents reported favourable attitudes toward condoms, many had not used condoms during their last experience with casual sex. Women reported stronger intentions to use condoms during casual sex than did men, but there was no gender difference in actual condom use. The findings underline the value of focusing on casual sexual relationships, and we hope that these results will encourage other researchers to study casual relationships in a diversity of contexts.