The use and abuse of drugs among youths is a continuing problem, particularly as they relate to criminal activity and delinquency. There is a continuing perception that drug use is problematic in the United States, especially among youths. This chapter examines the measurement of drug use and illustrates the extent of the problem. It also points out that the relationship between drug use and delinquency is not entirely clear, with some studies showing that use precedes delinquency and others showing that delinquency precedes drug use. The actual relationship is probably a reciprocal one, with each behavior contributing to the other. The chapter examines the wide range of drug treatments and interventions.