Retrospective study of urinary heroin outcomes of a cohort (123) of patients commenced on a methadone treatment program. Significantly poorer outcomes were associated with urines positive for cocaine (OR 0.69 CI 0.59-0.81) benzodiazepines (OR 0.7 CI 0.53-0.93) with prescribing of low dose methadone (OR 0.65 CI 0.48-0.87), with urines positive for heroin at time of admission (OR 0.74 CI 0.56-0.97) and with behavioural sanctions (OR 0.8, CI 0.65-0.98). Improved outcomes were associated with granting of take away methadone (OR 1.34 CI 1.1-1.62). with an indication of improved outcomes associated with alcohol positive urines (OR 1.34 CI 0.95-1.9) and increased duration of clinic attendance (OR 1.21 CI 0.99-1.47). On multiple regression analysis low dose methadone (0.07 CI 0.01-0.33) prescribing remained negatively associated with urine heroin outcomes.