This study examines the associations among substance use and psychiatric disorders on arrests in a sample of 187 former recipients of Supplemental Security Income for drug addiction and alcoholism. Participants were interviewed at baseline and at 12, 18, and 24 months. Primary measures included urine tests for recent drug use, psychiatric and substance use disorders per DSM-III-R criteria, and official arrests gathered from criminal histories. Arrest data were considered in aggregate and by charge category using Cox regression survival models of time to arrest. The relationships among diagnosis, substance use, and arrests varied by arrest charge category with those actively using cocaine or diagnosed as schizophrenic most likely to be arrested for any charge while those with major depression the least likely to be arrested. Dependence on alcohol and antisocial personality disorder were strongly related to the likelihood of an arrest for a violent offense but schizophrenia was not. Based on the findings, it is recommended that future studies of the relationship between drugs and crime and psychiatric disorders and crime take into account the high rates of comorbidity. (Contains 2 tables.)