Transdermal Fentanyl was released in March 2002 in Japan after the acceptance of the insurance under the office of public health. Transdermal therapy is especially effective for patients having difficulty of oral intakes, and for home care cancer patients who suffer from chronic pain only if the therapy is feasible on the long-term basis. We report our cases for long-term cancer pain management with transdermal fentanyl. A total of 52 long-term patients with chronic cancer pain (28 men and 24 women with an average age of 63.5 years, range 46-74 years) were evaluated. The most prevalent cancers were colorectum (n=14), stomach (n=10), breast (n=8), esophagus (n=6), pancreas (n=6), and others. The duration of the transdermal therapy varied from minimum of 2 days to maximum of 630 days. Two patients on this therapy were longer than 500 days. The transdermal therapy was discontinued 2-37 days for 8 patients due to uncontrolled pain relief. Case report 1: A 72-year-old woman suffering from a relapse of pancreatic cancer with chronic back pain experienced a good pain relief after switching from 60 mg/day sustained oral release morphine to 2.5 mg transdermal fentanyl. During the long-term treatment, the transdermal fentanyl dosage had to be increased. Transdermal therapy was continued until the patient's death on day 601. The last fentanyl dosage was 7.5 mg. Transdermal therapy was given 319/601 days at home and 282/601 days in the hospital. Meanwhile, a little rescue suppository morphine was used as an adjuvant during the duration of transdermal therapy. Case report 2: A 73-year-old man suffered a relapse of rectal cancer. He experienced adequate pain relief with 40 mg oral sustained release morphine, but he was switched to 2.5 mg transdermal fentanyl. Transdermal therapy was continued until today on day 630. At present, fentanyl dosage is 20 mg. The patient has been treated at home for 622/630 days. He was hospitalized only once for 8 days because of dehydrations, and has been treated at home. Only a little rescue powder morphine was needed as an adjuvant during the duration of transdermal therapy. In these 2 cases of long-term cancer pain management, transdermal therapy has resulted in good pain reduction and the side effects with transdermal therapy were not noted. Transdermal fentanyl can be recommended for treatment of palliative cancer pain at home.