The present study, involving 132 narcotic addicts with multiple periods of addiction, examines trends in criminal activity and drug use over successive periods of addiction and successive periods of nonaddiction during an average 15-year addiction career. Significant decreases over successive addiction periods were found for four (of five) categories of crime: theft, violence, drug distribution, and“other”crime (primarily gambling). These results appear to be accounted for by a disproportionately high level of crime during the first addiction period. Criminal activity, most notably theft and violence, decreased over successive periods of nonaddiction, though not significantly. Although more evidence is needed, a particularly large addiction vs nonaddiction disparity in crime rates for Hispanic addicts revealing a low propensity for crime when not addicted suggests that crime reduction may be a reasonable objective in the treatment of these individuals. With regard to drug use over the addiction career, the most dramatic increases over time were found for illicit methadone and cocaine. Rates of heroin and marijuana use declined. Generally, nonnarcotic drug use, other than use of cocaine and Valium, tended to decrease progressivelyovertime regardless of addiction status. These results, along with findings relevant to the“maturing out of addiction,”are discussed.