OBJECTIVES: An update of health economics analysis of type 2 diabetes mellitus (T2DM) in adult population in Turkey was performed. The primary objective of the analysis was to determine the direct cost components caused by T2DM and its complications. The relationship between metabolic complications and cost components is reported in this presentation. METHODS: Forty centres were selected from the list of centres in which adult T2DM patients were followed on a routine basis. These centres were representative of the country, since they were selected by two-stage cluster sampling. Medical files were reviewed for two to five years prior to the study. Item prices were obtained from the Ministry of Health and Social Security Organization of Turkey. Costs are calculated simply as the total of all frequency-price products (1€ = 2.321 Turkish Liras; Feb 2012). RESULTS: A total of 942 patients’ data were included in the analysis. During the previous five years, 28.0% of the patients had at least one visit or hospital stay related to metabolic complications (incl. diabetic ketoacidosis, hyperglycemic hyperosmolar state, hypoglycemia) and poor glycemic control. Total annual costs were 549.46€ and 364.52€, in patients with and without metabolic complications, respectively. Costs related to treatment, laboratory tests and healthcare services were 270.46€, 61.49€ and 32.57€, respectively, in patients without metabolic complications. Whereas costs related to treatment, laboratory tests and healthcare services were significantly higher in patients with metabolic complications (383.90€, 88.93€ and 76.64€, respectively; all p-values<0.01). CONCLUSIONS: All components of cost increased by 35% to 135% with the presence of metabolic complications. Whatever this relationship is based on (whether a direct association between acute metabolic status and the costs or an indirect association via the relationship between metabolic control and systemic complications), better metabolic control will significantly lower the cost of management of DM.