Background: The high prevalence and chronic nature of psoriasis leads to high costs in relation to the treatment and control of the disease. A number of clinical trials have shown that a combination therapy of calcipotriol cream (Daivonex®/Dovonex®, Leo Pharmaceutical Products) and ultraviolet B phototherapy (UVB) decreases the total number of UVB exposures required compared to UVB treatment alone. From a societal point of view, the addition of calcipotriol to UVB therapy could achieve cost savings due to the fewer UVB treatments needed and the reduced travelling and time off work for patients. Fewer UVB exposures may also have other beneficial effects, i.e., shortened waiting lists and less risk to patients of developing cancer or photoaging of the skin. Objective: To compare the cost-effectiveness of treating psoriatic patients in the Netherlands with calcipotriol cream used daily combined with twice weekly UVB treatments to emollient used daily combined with UVB given 3 times weekly. Methods: Based on the clinical results from a Canadian trial, a decision-analytical model was constructed to simulate treatment outcomes and estimate the costs of managing psoriatic patients in the Netherlands over a period of 20 weeks from initiation of therapy. Unit costs and details of standard treatment protocols were collected from Dutch dermatology centres in hospitals and the community for use in the model. Other therapies, such as topical corticosteroids, tar or dithranol were not investigated in this analysis. Results: The total cost of managing psoriatic patients in the Netherlands over a 20-week period is estimated as EUR 1,175.90 for those treated with calcipotriol and UVB and EUR 1,212.14 for patients treated with emollient and UVB. Thus, the former treatment, adding calcipotriol to UVB phototherapy, provides a minor cost saving of EUR 36.24 (3%) compared to the cost of UVB treatment alone. Sensitivity analyses demonstrated that these results are sensitive to changes in the cost of UVB treatment. Conclusion: Calcipotriol treatment combined with UVB phototherapy is a cost-neutral alternative to UVB phototherapy used with an emollient. The patients achieve treatment success in the same time on both treatments but the former, with calcipotriol, requires less exposure to UVB radiation. The additional drug costs from using calcipotriol are offset by savings from the fewer UVB sessions required. Essential beneficial effects for patients are less inconvenience, less risk of developing photoaging of the skin and less exposure to potentially carcinogenic radiations.