To evaluate the rehabilitation accomplishments of a methadone clinic in a New York City hospital, data were collected on 81 patients attending the clinic. Information was obtained on drug habits and on how patients financed their heroin addiction. Patient ages ranged from 20 to 62 years, with a mean age of 37 years, and patients had generally used heroin for many years. The daily heroin cost varied between $0 to $150, with a mean daily cost of $34.85. Criminal means of financing heroin addiction were usually employed, suggesting that most patients attending the clinic were hard-core criminal addicts. The money spent on methadone maintenance averted the need for a similar amount to be spent on jail and hospital costs, but methadone maintenance facilitated a certain degree of rehabilitation. Earning activities of the 81 heroin addicts during the 12 months before starting methadone maintenance are evaluated. The economic analysis also focuses on patient occupations before and after drug treatment, medical and social costs of heroin addiction, and imprisonment costs. 6 references, 6 tables, and 1 figure