Despite the fact that some individuals appraise their sexual cognitions negatively and/or experience negative affect in association with their sexual fantasies, sexuality researchers have not differentiated between positively and negatively experienced sexual cognitions. As part of a larger study, we investigated the frequency, diversity, and content of positive and negative sexual cognitions. Two-hundred and ninety-two (148 women and 144 men) heterosexual undergraduate students completed a sexual cognition checklist requiring them to report the frequency with which they experienced each of 56 sexual cognitions as positive and as negative. Results revealed that overall, respondents reported more frequent and more diverse positive sexual cognitions than negative sexual cognitions. However, men reported both more frequent and more diverse positive and negative sexual cognitions than did women. Although there was a significant relationship between the contents of positive and negative sexual cognitions, the most commonly reported positive sexual cognitions differed from the most commonly reported negative sexual cognitions. Men and women also differed in the frequencies with which they reported specific positive and negative sexual cognitions. These results are discussed within the context of the utility of differentiating between positive and negative sexual cognitions.