Diabetes Mellitus type-1 (DM1) is a high-incidence, chronic disease that increases morbidity and mortality, in Spain 5,000 new diagnosed patients per year have been estimated. DM1 chronic complications are the main cause of resource health care utilization and death among diabetic patients. DM1 is one of the most important causes of death, occupying third place for women and seventh for men in our country. Continuous Subcutaneous Insulin Infusion (CSII) reduces incidence of Diabetes-related complications when compared with Multiple Daily Injections (MDI) for Type-1. OBJECTIVE: The aim of the study was to project the costs and clinical benefits of CSII vs. MDI in the long term for DM1 patients in Spain. METHODS: An adaptation of the CORE diabetes model was carried out for the Spanish setting. Clinical and economic data were retrieved from published studies and SOIKOSTM Spanish's health care cost database. The analysis was run over a lifetime horizon from a NHS perspective, and direct costs and benefits were actualized to euros 2004 and discounted at 3% annum. RESULTS: Preliminary results shown that treatment with CSII was associated with an improvement in life expectancy (LE) of 0.859 and 0.836 Quality-Adjusted Life-Years (QALY's), compared to MDI. This was accompanied by decreases in cumulative incidence of complications. Mean total lifetime costs were 25,463 € more expensive with CSII treatment vs. MDI. This results in an incremental cost effectiveness ratio of 30,453 €/QALY with CSII compared to MDI group. CONCLUSION: Improvements in glycemic control associated with CSII vs. MDI lead to increase LE and QoL due to reduced incidence of diabetes-related complications. CSII is cost effective compared to MDI according to accepted Spanish threshold.