According to the three step-ladder analgesics in patients with cancer pain, adjuvant drugs are required for pain relief according to the pain character and also to reduce side effects of opioids. Pain clinicians sometimes want to decide to jump directly from naive and mild opioid to transdermal therapeutic system (TTS) fentanyl with less side effects. We investigated the safety, efficacy, and satisfaction of the patients of TTS fentanyl converting from opioid-naive and mild-opioid with adjuvant drug medications in related to dose cascade of TTS fentanyl. Both opioid-naive (n=3) and opioid-using (n=34) patients started with TTS fentanyl in the lowest available delivery rate (25 microg/hr) with rescue medication. A numeric rating scale (NRS, from 0=no pain to 10=worst pain imaginable), satisfaction of the patients with the transdermal therapy and side effects were recorded everyday during 29 days. Average reductions of NRS scores were 1.79 and 2.77, and the mean doses were 35.14 and 44.12 microg/hr on the 15th and 29th day, respectively. Reported level of satisfaction with the transdermal patch and generalized pain management were 'completely satisfied' and 'satisfied'. Frequent side effects were nausea, vomiting, and constipation. In conclusion, initial application of TTS fentanyl with proper adjuvant medications is effective, safe, and well tolerated.