Methadone hydrochloride is an effective, inexpensive, and relatively safe opioid to use in the treatment of patients with chronic pain. It is especially effective in management of pain during the final stages of life, as it is the only long-acting analgesic available in liquid form. However, because methadone has a long half-life, individual wide variations, and potential for accumulation and overdosage, physicians must judiciously and conscientiously prescribe it. Also, they should closely monitor patients during the titration phase and educate them with regard to basic pharmacologic properties and potential side effects. A plan to start at low doses and proceed slowly is applicable to methadone.