Women and men were also grouped according to length of time in treatment and costs for discharged patients (patients with less than 1 year of treatment in their index DATOS methadone treatment program). A total of 144 women and 250 men were involved in the study. Treatment costs were estimated from program data reported in the 1992 National Drug and Alcohol Treatment Unit Survey (NDATUS). Estimates of the costs of crime before, during, and after methadone treatment and at follow-up were calculated by multiplying each reported illegal act by the tangible cost of that crime. Nine types of crime were considered: aggravated assault, burglary, theft, robbery, forgery, fencing, gambling, prostitution, and drug law violations. The hypothesis that benefits regarding costs of crime to society would differ by gender was supported. Overall, the cost-benefit ratio for women was 3.62 and for men was 2.60. Positive social net benefits (total treatment benefits less cost of treatment) for women were $9,599 and for men were $5,223. Within gender there were slight differences between the benefit-cost ratios for discharged and continuing patients. The study concluded that economic benefits from methadone treatment were shown. Treatment investments for both women and men who were discharged and for those who continued in treatment provided economic benefits that showed returns ranging from 2.5 to almost 4 times the cost of treatment investments. 5 tables and 24 references