The hypotheses tested were that greater commitment to abstinence-oriented policies is associated with decreased retention of patients and that strong commitment to abstinence- oriented policies tends to overcome the improved retention usually associated with higher doses of methadone. A total of 280 patients recently enrolled in single-person, private methadone programs operated by independent, private physicians in Sydney, Australia, were interviewed and followed for 8 years. An instrument to measure methadone staff's commitment to abstinence- oriented treatment policies was developed and tested in a survey of 90 staff working in Sydney's 10 public methadone clinics. The findings show that doctors' scores on a scale that measured commitment to abstinence-oriented policies were significantly associated with retention of patients in their programs. The more strongly physicians were committed to abstinence-oriented policies, the more likely patients were to be prematurely discharged from their programs. The abstinence-oriented programs had worse retention because they generally used lower maximum doses of methadone. Further, abstinence-orientation reduced the beneficial effect of higher maximum methadone doses on retention. This is probably because patients in abstinence-oriented program generally receive their maximum dose for only a short period before undergoing a prolonged withdrawal. These findings suggest that more attention should be paid to the effect of staff attitudes and beliefs on the effectiveness of maintenance treatment. 2 tables, 2 figures, and 23 references