en تخصصي Special پژوهشي Research Objective: Type 2 diabetes mellitus (DM-2) is a chronic and progressive metabolic disorder known as a serious threatening condition in the individual and society. Type 2 diabetes mellitus is known as the major cause of cardiovascular diseases (CVD). Contradictory evidences about the effect of omega-3 fatty acids on CVD risk factors, particularly hypertension. The aim of this study was to determine the effect of omega-3fatty acids supplementation on blood pressure in DM-2 patients. Materials and Methods: This is a double-blind, placebo-controlled clinical trial on patients referred to Yazd Diabetes Research Center. Seventy DM-2 patients were randomly assigned to receive either 2 g/day omega-3 soft gels (OG) or 2 g/day placebo (PG) for 6 weeks. At the beginning and end of the study, blood pressure was measured and compaired Results: Fifty nine percepts of patients in OG and 41% in PG had hypertension. Initially, there was no significant difference in the mean of age, body mass index (BMI), systolic blood pressure (SBP), diastolic blood pressure (DBP) and duration of diabetes between two groups. At the end of the study, the mean of SBP, DBP and differences between groups were not significant. Conclusion: Consumption of 2 g/day omega-3 supplement for6 weeks has no significant effect on systolic and diastolic blood pressure in DM-2 patients. Type 2diabetes, Hypertension, Omega-3 fatty acids, Docosahexaenoic acid (DHA), Eicosapentaenoic acid (EPA) 54 59 http://ijdo.ssu.ac.ir/browse.php?a_code=A-10-30-45&slc_lang=en&sid=1 Faezeh Poursoleiman No MSc student, Department of Nutrition, Faculty of Health, Shahid Sadoughi University of Medical Sciences, Yazd, Iran Hassan Mozaffari-Khosravi Yes Department of Nutrition, Faculty of Health, Yazd Diabetes Research Center, Shahid Sadoughi University of Medical Sciences, Yazd, Iran Javad Zavar Reza No Department of Clinical Biochemistry, Faculty of Health, Shahid Sadoughi University of Medical Sciences, Yazd, Iran Ali Dehghani No Department of Biostatistics and Epidemiology, Faculty of Health, Shahid Sadoughi University of Medical Sciences, Yazd, Iran