We investigated the outcomes of a 21-day inpatient drug detoxification and rehabilitation program including length of stay, transfer to further treatment, and HIV risky behavior. Clients (n= 567) were predominantly White, male, currently unemployed, and their treatment was not covered by third party payment. 78% were detoxified with methadone. The median length of stay was 18 days. Higher education, not living with spouse or children, English as primary language, admission during fall or winter months, and greater knowledge of HIV transmission were independent predictors of greater length of stay. Among those with follow-up (n= 450), 19% were transferred to residential drug-free programs and 7% to outpatient programs. Taking into account loss to follow-up, the overall rate of treatment transfer could be as low as 21%. Greater length of stay was associated with higher rates of transfer to residential treatment. Relapse rates to either any drug use or injection drug use were lower among subjects transferred to residential treatment than either clients transferred to outpatient programs or those with no further treatment. Among subjects who continued to inject drugs at follow-up, no reduction in HIV risky behaviors was found regardless of further treatment. We conclude that detoxification programs have the potential for reducing relapse to drug use when followed by residential drug-free treatment.