OBJECTIVES: cost-effectiveness estimation of treatment with a fixed-dose combination of diclofenac and misoprostol (FDC D-M) 50 mg/200 mcg bid compared with diclofenac (D) 50 mg bid in prevention of NSAID-induced ulcers in rheumatoid arthritis (RA) patients in Poland. METHODS: Decision model for FDC D-M in the Polish health-care context was developed, based on the use of epidemiological and clinical data from literature and local data on health-care resource utilisation and unit cost. Only direct medical costs are analysed. The perspective of health-care payers (sickness funds + patients) is taken. A time horizon is 3 months, but consequences of a longer time horizon are discussed. Cost-effectiveness was calculated for the treatment of all RA patients and risk groups only. Effectiveness was expressed in life-years saved. The cost-effectiveness threshold, calculated on basis of 1-year haemodialysis treatment cost (15 600 USD) or national GDP per head at PPP (6300 USD), was suggested to asses if the FDC D-M therapy should be adopt. RESULTS: Analysis showed, that FDC D-M treatment in RA patients gives additional life years for extra costs. In all RA patients (aged 65) 1 LYG costs 33 700 USD. Cost per LYG was below suggested cost-effectiveness threshold only in patients at high risk (history of peptic ulcer disease or GI bleeding, disability - mHAQ > 1,5, concomitant antacid therapy). One-way sensitivity analysis showed, that outcomes are sensitive to changes in: price differences between FDC-D-M and D, ulcers percentage and the misoprostol efficacy. CONCLUSION: FDC D-M treatment in Poland is cost-effective only in RA patients at high risk for NSAID-induced ulcers.