Background and Purpose: Diabetes is a common disorder in carbohydrate metabolism and a chronic disease. Blood pressure is being seen in 70% of diabetes patients. The role of Cumin in treatment of complications of diabetes also has been proven. Therefore, the aim of this study was to evaluate the effect of cumin on blood pressure of patients with diabetes type two. Materials and Methods: This study was performed by double-blind clinical trial on 50 diabetic type two patients, who referred to Imam Khomeini Diabetes Clinic in Zabol. The criteria for entry into this study includedDiabetes type two, Blood pressure higher than 140 mmHg on 90 mmHg, at least having a 6 months history of infection of diabetes, lack of mental disorders, non-insulin therapy, non-pregnancy and lactation, having a drug program with consideration of type of medication and did not use tobacco and alcohol. In case of recognizing any of these issues, the sample was excluded from the study. Samples were randomly divided into two group of 25 individuals without splitting during the study. At first, blood pressure was measured and then a cumin extract group and placebo control group consumed placebo for two months. Patients’ blood pressure was re-measured. The software SPSS version 22 was used to analyze the data. Findings: The difference in mean systolic and diastolic blood pressure in the cumin consumed group was statistically significant (P0.05). But, this difference was statistically significant after intervention (P<0.0001). Discussion and Conclusion: In the present study, the effects of cumin on the improvement of blood pressure were observed. No special side effects were observed during the course of the project. Based on this, it can be said that complementary cumin can be effective in controlling complications of diabetes, including hypertension. Key words: Cumin, Blood pressure, Diabetes.