To treat cancer pain, physicians often decide to jump directly from step 1 of the World Health Organization (WHO) analgesic ladder to step 3. The use of transdermal fentanyl in patients with cancer pain who had either used no opioid before, or only codeine, is evaluated in the present trial. Both opioid-naive (N = 14) and codeine-using (N = 14) patients started with transdermal fentanyl in the lowest available delivery rate (25 microg/hr). Immediate-release oral morphine was present as "rescue" medication. Transdermal fentanyl provided good to excellent pain relief in the majority (68%) of these patients. During the study, 5 patients continued with 25 microg/hr, and the others used a higher dose. Clinically relevant respiratory depression was not observed. The common side effects of opioids were found; constipation was mentioned by 3 patients (11%). Transdermal fentanyl appeared a safe analgesic in these opioid-naive cancer pain patients. In this study, WHO step 2 could be skipped without untoward complications.