Objective: To analyze the economic consequences on staff time in post-operative wards in Sweden and Denmark of two modalities for treatment of post-operative pain, the fentanyl HCL iontophoretic transdermal system (fentanyl ITS) versus patient controlled intravenous analgesia (IV-PCA). Methods: Current postoperative pain management is labor intensive. Fentanyl ITS is a new modality for moderate-to-severe postoperative pain. Clinical efficacy and side effects incidence have been reported as mainly the same for fentanyl ITS and IV-PCA in several randomized clinical trials. A cost analysis was therefore performed. Staff resources in post-operative wards were calculated based on findings from a Nordic Delphi panel where the participants (nurses and anesthesiologists) from Sweden and Denmark working with post-operative patients should determine the total time required to complete all tasks involved in fentanyl ITS and IV-PCA use and assess differences in staff time between the alternatives. The panelists identified the following tasks: set up, routine patient care, dosing, routine replacement, troubleshooting, and discontinuation of post-operative pain management. Staff costs were calculated based on official wages statistics for specialists and nurses in postoperative care. Costs were calculated in 2007 prices. Results: Based on the panel information, the total post-operative staff time requirements per patient was 70 minutes for fentanyl ITS versus 146 minutes for IV-PCA. Most staff resources were spent on set up and routine patient care for both treatment alternatives. The post-operative staff cost per patient was calculated at €27 and €57 in Sweden and €31 and €66 in Denmark, respectively. Conclusion: The staff costs of post-operative management in post-operative wards with fentanyl ITS is 53% (€30) lower per patient in Sweden and 53% (€35) lower in Denmark compared with IV-PCA. Additional health-economic analyses of total resources used for post-operative pain management, including material costs, based on clinical observations would be valuable.