Latinos have recently become the largest minority in the United States. High fertility and high immigration rates suggest continued high rate of growth. Alcohol and illicit drug use within this population give reason for concern. Beginning in early adolescence, Latinos and Native Americans lead the nation in alcohol and illicit drug use. They also have a high need for alcohol and illicit drug treatment compared to Whites and African-Americans. Research concerning ethnic differences is reviewed in order to gain an understanding of the patterns and trajectories of substance use within the Latino community. Prevention and treatment interventions specific to Latinos are described, and gaps in the literature are noted. Finally, implications of the current research findings for social workers and recommendations for future research are discussed.