OBJECTIVES: To compare cost-utility of detemir and NPH insulin in intensive insulin therapy (IIT) of type 1 diabetes patients, cost-utility of detemir and NPH insulin in basal-bolus IIT or added to oral antidiabetes treatment in type 2 diabetes. To estimate the impact of insulin detemir reimbursement on the budget (BIA) of the National Health Fund in Poland. METHODS: Cost-utility analysis from payers’ (Polish National Health Fund and patient) perspective in lifetime horizon was conducted using CORE Diabetes Model. The effectiveness data were derived from clinical studies. The model default values and experts’ opinion served as data sources for resource use. BIA: Two scenarios were compared: before and after reimbursement of insulin detemir with reimbursement limit equal to the drug price. Population of patients treated with insulin detemir was assumed to consist of type 1 and type 2 patients with documented episodes of severe hypoglycaemia, undergoing IIT (with use of standard basal insulin NPH). RESULTS: CUA: Insulin detemir in type 1 and type 2 diabetes patients is more costly and more effective than NPH insulin in terms of patients’ life expectancy and quality adjusted life years (QALYs) gained - cost per QALY gained is: PLN161,138 (€47,512) in type 1 diabetes treatment; PLN603,107 (€177,829), assuming use of basal-bolus intensive insulin therapy in type 2 diabetes; PLN72,583 (€21,401), assuming use of long-acting insulin with oral antidiabetes drugs in type 2 diabetes. BIA: Predicted number of patients annually treated with insulin detemir amounts to 6 736. In case of insulin detemir reimbursement yearly public payer’s (NHF) expenditures for long-acting insulins used in intensive insulin therapy would increase by PLN 6,1mln (€1,8mln), i.e. 20% compared to a current situation. CONCLUSIONS: Type1 and type2 diabetes treatment with insulin detemir offers an improvement of patients’ quality of life, being more costly than standard intensive insulin therapy with NPH.