Abstract    INTRODUCTION: Diabetes mellitus is the most important endocrine disease worldwide. Scientists recommend consumption of low glycemic index (LGI) foods for prevention and control of diabetess. This study was designed to test the effects of cooked lentil as a LGI food on blood glucose and lipid profile among type 2 diabetic patients.    METHODS: In a randomized cross-over clinical trial, 30 individuals with type 2 diabetes were randomly divided into 2 groups (A and B). At the 1st step, group A followed the normal diet and group B followed normal diet plus 50 g cooked lentil and 6 g canula oil substitute of 30g bread and 20 g cheese. After 6 weeks these two groups stopped their diets and put on wash out period for 3 weeks and later the diets were switched between them and continued for another 6-week-period. Anthropometric measurements, dietary intakes, serum lipids and glucose levels were determined at the beginning and the end of each period. Data was analyzed by Food Processor II and SPSS-13 softwares.    RESULTS: Body mass index, LDL-C, HDL-C ,triglycerides and serum Fructozamine were not significantly influenced by treatment whereas total cholesterol and fasting blood glucose decreased significantly (P < 0.05).    CONCLUSION: Cooked lentil consumption as a LGI food in breakfast can control FBS and serum total cholesterol. It might be a good regimen for improving glycemic control in type 2 diabetic patients.      Keywords: Diabetes mellitus, Lentil, Lipid profiles, Blood glucose, Glycemic index.