We examined the concurrent and longitudinal associations between risk factors and substance use for a sample of high school students. Ten risk factors were defined that assessed numerous important personal and social areas of life. These factors were found to be associated with ever using, frequency of use, and heavy use of cigarettes, alcohol, cannabis, and hard drugs. Few effects were noted for nonprescription medication. No sex differences were evident for number of risk factors. Finally, the number of different risk factors was predictive of increases in use of all types of substances over a one-year period, after controlling for initial level of use.