The purpose of this study was to examine the relationship of treatment outcomes in opioid detoxification to levels of counselor and peer alliance. Forty-one subjects were recruited from a larger, 180-day study of psychosocial treatment. Beginning at day 90, subjects completed monthly measures of alliance. Outcome measures included treatment retention, drug use and self-reported HIV risk. Measures of alliance were found to be internally consistent and moderately stable over time. During the final 30 days of the methadone taper, higher levels of both types of alliance were associated with less use of illicit opioids. Alliance with counselor was associated with less frequent needle sharing. For subjects who could be located for 30-day follow-up, greater alliance with peers was associated with more frequent HIV (sexual) risk behaviors. Results suggest that treatment outcome may be improved through approaches that address a patient's alliance with both counselor and peers.