Analysis of data from 1394 undergraduates at a large southeastern university were used to assess the degree to which the stereotype that "men are dogs" (sexually-focused cheaters) is justified. Results suggest that this stereotype is unjustified since the majority of males: (1) define behaviors from kissing to anal sex as cheating; (2) predict that they will not cheat on their partners; and (3) report never having cheated on a partner. However, compared to those of the women, the frequencies with which men report cheating are high. Approximately one-in-five males in a "monogamous" relationship reported having had oral sex and/or vaginal intercourse with someone else (22.2% and 19.7% respectively) and withheld this information from their partners (thus leaving the partners vulnerable to STD/HIV infection). Implications and limitations of the study are identified.