OBJECTIVES: The aim of the study was to estimate the costs of treating venous leg ulcers (VLU) in Sweden and the UK and to compare and discuss possible differences between the two countries. METHODS: Costs for VLU treatment were estimated with a health economic model based on resource use data obtained from prospectively collected patient data, expert panels in Sweden and the UK, and scientific publications. The model simulated costs for healing of an initial ulcer, costs for prevention of new ulcers in an ulcer free period, and costs of treating second ulcers for a period of one year. Simulations were performed for ulcers of durations <6 months or > = 6 months and sizes <10 cm2 or > = 10 cm2. RESULTS: For an initial ulcer with a duration > = 6 months and a size > = 10 cm2 the mean total treatment costs were €2295 in Sweden and €1994 in the UK. Costs of prevention in the ulcer-free period were €127 in Sweden and €45 in the UK. Total costs for one year were €2797 in Sweden and €2138 in the UK. Labour accounted for most of the costs in both countries, while costs of dressings and other material were about 14 % for the initial ulcer in Sweden and 21 % in the UK. Costs of surgical procedures were low in both countries. Treatment costs decreased in patients with shorter ulcer duration and smaller ulcer size. Nevertheless, the difference in costs between the countries remained in all groups. CONCLUSIONS: The most important factor influencing treatment costs in the two countries is the frequency of dressing changes resulting in higher cost of treatment of VLU in Sweden. Other differences of importance are the organisation of treatment and management of VLU.