OBJECTIVES: Health expenditure to treat and prevent T2DM and its complications was estimated at USD 345 million for OECD countries in 2010.  These costs pose great burden to national health system’s budget, which is already under pressure. In Greece there are no studies that provide information on the costs of T2DM patients including the cost of complications, hospitalizations and co-morbidities. The current study aimed to estimate the total cost of T2DM patients from a third party payer perspective. METHODS: A retrospective research study was performed in four major hospital diabetes centers and 211 patients with at least 10 years of T2DM from diagnosis.  Patients were categorized in two groups, controlled and uncontrolled. Hospitalization and management of complications was based on DRG cost. Pharmaceutical and diagnosis cost was based on official NHS prices.  Health care cost corresponds to 2012 Euros and the perspective used was of the Social Security Fund. Subgroup analysis was performed in order to evaluate the cost difference between controlled vs. uncontrolled, obese non-obese and various other subgroups. RESULTS: The mean age of patients was 72.9±8.1 years with mean T2DM duration 21.2±7.5 years, and mean HbA1c 7.3±1.0%. The mean average yearly cost of T2DM was €7.111 whereas only the18.8% was attributed to cost of antidiabetic drugs. Controlled patients (HbA1c ≤ 7) cost on average 6.366 and uncontrolled (HbA1c>7) €7.783. The mean hospitalization and complication cost was €2.456. It was found no difference of mean hospitalization and complication cost between controlled and uncontrolled patients (p=0.09). Co-morbidities cost absorbs the majority of the budget and was the differentiating factor between two groups.  Few patients (21.8%) reported admission to hospital with similar hospitalization rates on number and duration between the two groups. CONCLUSIONS: T2DM is an expensive to treat disease with very high cost complications with economic and societal burden.