Background: For terminal cancer pain management, controlled-release oral morphine (morphine sulfate tablet, MST) is a simple and convenient regimen. Recently, fentanyl transdermal therapeutic system (F-TTS, transdermal fentanyl) has been developed and became one of the alternative ways of providing adequate pain relief. This open prospective study was designed to compare the analgesic efficacy and safety of MST and transdermal fentanyl in the management of terminal cancer pain. Methods: In this open comparative and randomized study, 64 terminal cancer patients received one treatment for 15 days, controlled-release oral morphine (MST group) or fentanyl transdermal therapeutic system (F-TTS group). Daily diaries about the vital sign, visual analogue scale (VAS) for pain, opioids requirement, co-anagesics, adjuvant drugs and adverse effects were completed with 24 patients in MST group, 18 patients in F-TTS group. Results: The majority of patients in both treatment groups were late-stage cancer and their distribution was not different in both groups. Daily opioids requirement was 126.4 mg in MST uced in F-TTS group (P<0.05). The incidence of nausea, vomiting and constipation was lower in F-TTS group (P<0.05). Patients satisfaction was similar, but F-TTS patient group favored continous use of same treatment compared with MST group after the study was finished. Conclusions: Transdermal fentanyl seems to be safe and similar analgesic effect to controlled-release oral morphine for the control of the terminal cancer patients. However, transdermal fentanyl provides a simpler and more convenient especially in respect to constipation, nausea & vomiting. To determine the exact analgesic effect, cost-effectiveness and complications, controlled trials should be followed.