OBJECTIVES Comparison of the changes in QoL of diabetic patients after pharmaceutical cognitive service with SF-6D. METHODS Tree step methodology was created and applied towards the patients with type 1 and type 2 diabetes. On first the QoL of 146 diabetic patients was assessed with the Bulgarian version of SF-6D. Then educational program for the diabetic patients was developed and applied during the day of their visits in community pharmacy from June to September 2013. At the end the changes in the QoL after the pharmaceutical cognitive service was assessed in the group of 24 patients. RESULTS The mean age of patients included in the first step was 57.39 years (SD 17.087; 95%CI 54.60-60.19). 76% of them were with type 2 diabetes and 73% suffers from diabetes complications. The mean SF-6D score was 0.629 (SD 0.289; 95%CI 0.58-0.68). After the pharmacy program the type 2 diabetic patients showed better quality of life index 0.7133 that was 10% higher than the initial score 0.6089. In the patients with type 1 diabetes the improvement of QoL score is with 3 %. The patients were with mean SF-6D scores: 0.667 on the first visit in the pharmacy and 0.690 after the educational service. CONCLUSIONS The study suggests the SF-6D is a valuable tool for QoL assessment of diabetes patients in Bulgaria. It also shows that SF-6D could be used for pharmacy program evaluation in diabetes patients. Regarding the pharmaceutical cognitive service in diabetic patients is evident that they have a potential to improve the QoL in patients with diabetes mellitus and their impact could be measured with SF-6D.