This study examined childhood sexual abuse (CSA) in gay and bisexual men. We compared the conventional definition of CSA based on age difference with a modified definition of CSA based on perception to evaluate which definition best accounted for problems in adjustment. The sample consisted of 192 gay and bisexual men recruited from a randomly selected community sample. Men's descriptions of their CSA experiences were coded from taped interviews. Fifty men (26%) reported sexual experiences before age 17 with someone at least 5 years older, constituting CSA according to the age-based definition. Of these men, 24 (49%) perceived their sexual experiences as negative, coercive, and/or abusive and thus were categorized as perception-based CSA. Participants with perception-based CSA experiences reported higher levels of mal-adjustment than non-CSA participants. Participants with age-based CSA experiences who perceived their sexual experience as non-negative, noncoercive, and nonabusive were similar to non-CSA participants in their levels of adjustment. These findings suggest that a perception-based CSA definition more accurately represents harmful CSA experiences in gay and bisexual men than the conventional age-based definition.