This study investigates and compares the responses of 132 opiate addicts to a 10-day or a 21-day in-patient oral methadone withdrawal regime. For both groups, symptom severity (on the Opiate Withdrawal Scale) steadily increased through the methadone withdrawal phase, and peaked near the point of completion of the prescribed drug, declining slowly thereafter. Patients on the 10-day programme reported significantly higher peak withdrawal scores than those on the 21-day programme. Although the proportions who completed detoxification were similar, there was a significantly higher drop-out rate immediately after detoxification for the 10-day group. The possible benefits and handicaps of the two withdrawal schedules are considered and recommendations are proposed for further refinement of the present widely adopted approach.