A sample of 279 male heroin addicts admitted to methadone maintenance programs in Southern California were interviewed between 1978 and 1980. These individuals reported high rates of drug trafficking and over 250,000 property crime-days which resulted in 6,251 arrests. Analyses indicate that offense rates and related social and economic costs were at their highest during periods of addiction. The aggregate cost to society, including the criminal justice system and drug treatment intervention, is conservatively estimated at $85 million, averaging $20,000 per subject per year. These findings provide an empirical basis against which to evaluate the cost-effectiveness of alternative interventions. 9 footnotes and 8 tables (Author abstract modified)