Three hypotheses have generally governed studies on drug use and crime: (1) drug use leads to crime; (2) crime leads to drug use; and (3) both drug use and crime are manifestations of a general orientation towards delinquency and are not causally related. Early studies of juvenile delinquents, drug use, and crime include a series of 1949-56 studies done by Chein in New York, which do not show any clear causal relationship between drug use and delinquency. Polonsky and others found that delinquent youth frequently become involved with drugs as part of their delinquent behavior. Both these studies indicate that there are other variables affecting patterns of drug use and crime such as ethnicity, social milieu, and opportunity. Still other studies of delinquents supported the contention that both drug use and delinquency are manifestations of a general orientation toward crime, but did not eliminate the possiblity of a causal relationship between the two. There is considerable consensus in the studies that involvement in delinquent behavior precedes any use of illicit drugs. There is good evidence that drug use follows involvement in serious delinquent acts. Studies which have permitted control for prior delinquency levels have not found an association of drug use onset with increases in delinquency, leading to the conclusion that drug use per se does not account for increasing delinquency. Strong evidence is provided from several studies that marihuana use and delinquency are not causally related but are both symptoms of involvement in a general deviant subculture. Some of the major needs for future research center around the issues of theoretical linkage between drug use and delinquency (linkage between specific drug use and specific types of delinquent acts), the relationship between drug use and delinquency for drugs other than longitudinal study of delinquency and drug use. A total of 30 references are included. For the full text of the drug use and crime report, see NCJ 40293.