As limited research exists on medical students' substance use patterns, including over-consumption of alcohol, the objective of this study was to determine prevalence and correlates of at-risk drinking among a national sample of medical students, using a cross-sectional, anonymous, Web-based survey. A total of 2710 medical students from 36 U.S. medical schools (1st to 4th year) completed the survey. Included in the instruments was a 10-item scale (AUDIT) to assess at-risk drinking behaviors within the last 12 months. Over 15% of the subjects (n = 412) scored positive for at-risk drinking (>/= 8). Multivariate analysis of the data revealed the following independent predictors were statistically significant (P </= 0.05) for at-risk drinking: being of younger age, male, unmarried, using illicit drugs, smoking tobacco products within the last 30 days, having low perception of risk, showing impulsive behavior, being depressed, and having gambling problems. Findings from this study provides initial data for investigating further associations between risky drinking behavior, lifestyle, and psychosocial factors, as well as effectiveness of curriculum or campus-wide policy interventions to reduce over-consumption of drinking among this population.