Twenty-two courses of oral methadone were given to control moderate or severe pain in 19 children with cancer. Of these, 21 courses gave adequate pain control for periods of 5 to 267 days (median 24 days). In 16 courses, methadone was continued until death or until the pain resolved; in five remaining courses, a change to parenteral narcotics was ultimately required. Toxicity was minimal. A safe starting dose of methadone appears to be 0.1 mg/kg given every 4 hours, or the equivalent total daily dose given less frequently, with escalation as required to achieve and maintain adequate pain control.