Objective: The college years represent a developmental transition during which the initiation and escalation of heavy drinking set the stage for lifelong difficulties with alcohol and other drugs. Evidence from studies of adolescents and young adults with ADHD suggests that college students with the disorder may be uniquely vulnerable to alcohol- and drug-related problems. However, no studies have examined substance use in college students with ADHD. Method: Tobacco, alcohol, illicit drug use, and associated impairment were examined in 91 college students with (n = 53) and without (n = 38) ADHD. Results: ADHD was associated with increased frequency of tobacco use, higher rates of dangerous or hazardous patterns of alcohol use, and higher levels of impairment related to marijuana and nonmarijuana illicit drug use, independent of conduct disorder history. Conclusion: These findings suggest that college students with ADHD may be at elevated risk for problematic patterns of substance use.