A 59-year-old woman with metastatic breast cancer experienced a poor response to increasing doses of hydromorphone, possibly related to the neuropathic nature of her pain. Ultimately, the cost of this treatment was more than $1000 per day. Administration of methadone, initially as an adjuvant and eventually as the sole analgesic, at a much smaller dose than expected resulted in very satisfactory analgesia, without the development of serious side effects. In addition, the cost of treatment decreased to less than $25 per day. This case illustrates the rationale and advantages for the use of methadone. Intraindividual variability in the response to various opioids is a factor to be considered when selecting analgesics. Methadone is a useful second-line or third-line opioid for the patient who is highly tolerant to other opioids, as it may demonstrate incomplete cross-tolerance with other agonist opioids. Switching of the opioid to methadone may be a worthwhile option to consider in managing patients who are highly tolerant to other opioids.