OBJECTIVE: to compare costs and effects of continuous terbinafine and intermittent itraconazole in the treatment of toenail onychomycosis in Poland. This was intended to facilitate the decision-making process in selecting the more cost-effective treatment for toenail onychomycosis. METHODS: L.I.O.N. study results were used to estimate effectiveness of terbinafine 0,25 g/d for 12 or 16 weeks (T12, T16) and itraconazole 0,4 g/d for 1 week in every 4 weeks for 12 or 16 weeks (I3, I4). The measure of treatment effectiveness was complete cure and average number of disease-free days per patient. Direct medical costs were estimated on the basis of current treatment patterns in Poland. The perspective of health care payers and time horizon of 72 weeks were taken. The decision model was used to quantify cost and effectiveness of alternative treatments. One-way, two-way sensitivity analysis and treshold analysis were performed. RESULTS: Cost/patient cured and cost/disease-free day were (in PLN, 1 USD=4,5 PLN)): for T12 - 2199 and 10,6 for T16 -2279 and 10,6, for I3 - 4207 and 16,9, for I4 - 4670 and 20,3. Incremental analysis suggests, that I3 and I4 are dominated programs, T12 and T16 are cost-effective. In deciding between them, the size of the available budget must be brought to bear. T12 ensures greatest effect within fixed budget. One-way sensitivity analysis indicated, that T16 would be optimal choice only when probability of complete cure for T16 was >0,57 or probability of complete cure for T12 was 0,41-0,43. In two-way sensitivity analysis T16 was optimal choice only when probablitity of complete cure I3 and T12 or I4 and T12 were changed simultaneously. The treshold analysis suggests, that I3 and I4 would be optimal, when the price of itraconazole would be decreased by 63%. CONCLUSION: In Poland T12 was the most cost-effective treatment of toenail onychomycosis.