In a large survey of college student drug use in the Denver-Boulder metropolitan area, almost one-third of students admitted to having used illegal drugs. The most commonly used illegal drug was marijuana, which had been used by 26 percent of the students. Amphetamines had been used by 14 percent and LSD by five percent. The authors explore attitudes toward drug use and drug legislation as well as mood states and reasons for drug use. Patterns of drug use are contrasted with a variety of demographic variables and with different college and university characteristics.