OBJECTIVES: To evaluate the long-term clinical and economic outcomes of treating adults and adolescents with type 1 diabetes with continuous subcutaneous insulin infusion (CSII) versus multiple daily injections (MDI) in Poland. METHODS: A validated model was used to estimate the lifetime impact of CSII-related improvements in diabetes control on quality-adjusted life-expectancy (QALE), occurrence of complications, and direct medical costs in two Polish type 1 diabetes cohorts (Adult - mean age 37.8 years, duration of diabetes 10.4 years, mean HbA1c 9.40%; adolescent - mean age 14.0 years, duration of diabetes 1.0 year, mean HbA1c 9.40%, no baseline complications). Treatment effects of CSII were defined from a meta-analysis as a reduction of 0.95% in HbA1c and a decrease in severe hypoglycemia (14.8 versus 62 events per 100 patient-years) compared with MDI. Future costs and benefits were discounted at 5% annually and projected over the patient’s lifetime. All costs were evaluated in 2006 Polish Zloty and converted to Euro (€). RESULTS: CSII was associated with improvements in QALE (0.35 and 0.46 quality-adjusted life-years [QALYs] for adults and adolescents, respectively) and fewer diabetes-related complications versus MDI. Over patient’s lifetime CSII versus MDI for adults and adolescents was projected to reduce the cost of renal disease by €865 and €413 and cost of hypoglycaemia by €576 and €3,463, respectively. For adults and adolescents CSII was projected to cost €9,309 and €19,294 more than MDI over a patient’s lifetime, respectively. CSII was associated with an incremental cost-effectiveness ratio (ICER) of €20,778 for adults and €14,968 for adolescents per QALY gained versus MDI. CONCLUSIONS: Based on the threshold proposed by the World Health Organization (4 times the Gross Domestic Product per capita, approximately €26,000), CSII treatment improves clinical outcomes and represents a cost-effective treatment option compared with MDI for patients with type 1 diabetes in Poland.