Self-report surveys obtained data from 620 inmates residing in 5 jails in the greater Philadelphia area. The data collection was part of an evaluation of the impact of a 12-week cognitive treatment program provided to jail inmates in 2000-2001. Survey questions measured inmates' feelings of depression and anxiety, antisocial personality, levels of self-control, and attachment and commitment to social bonds and legitimate social goals. Inmates were also asked about their involvement in drug use and drug-related problems, as well as criminal history. White and Hispanic inmates had similar levels of self-control, and Black inmates had higher levels of self-control than either White or Hispanic inmates. Drug-related problems were regressed on the measure of low self-control and other independent variables, in order to test the effects of self-control on antisocial behavior. Low self-control consistently had positive effects on drug-related behavioral problems for White, Black, and Hispanic inmates; moreover, the strengths of these effects were similar for all racial groups. Overall, the findings add to the growing body of literature that supports the key argument of the general theory of crime, i.e., that low self-control is linked to delinquency and crime regardless of race. 3 tables and 58 references