Objective: To examine the prevalence of drug-related sexual assaults, identify the frequency of assaults that occur following voluntary versus involuntary drug or alcohol consumption, and identify contextual correlates of drug-related assaults. Participants: College-student females (n = 314). Methods: Volunteers reported experiences with forcible and drug-related sexual assaults in the spring semester of 2004. Follow-up queries regarding the most severe drug-related assaults determined whether the assaults followed voluntary or involuntary alcohol or drug consumption. Results: 29.6% (n = 93) of the respondents reported a drug-related sexual assault or rape; 5.4% (n = 17) reported a forcible sexual assault or rape. Voluntary incapacitation preceded 84.6% of drug-related assaults and involuntary incapacitation preceded 15.4% of drug-related assaults. The majority of drug-related assaults (96.1%) involved alcohol consumption prior to assault. Conclusions: Drug-related sexual assaults on college campuses are more frequent than are forcible assaults and are most frequently preceded by voluntary alcohol consumption. (Contains 7 tables.)