The authors tested several theories using prospective data to explain the associations between drug abuse and crime in a community sample of 470 adults. Polydrug problems in early adulthood predicted both criminal behavior and polydrug problems in adulthood. Consequences of drug problems as a young adult included arrests and convictions for drug-related offenses, property damage, and driving under the influence of other drugs. Predictors of later polydrug problems included thefts, driving under the influence of alcohol and other drugs, arrests and convictions for drug-related offenses, and a lack of support for drug problems. Theoretical implications of these findings are discussed.