Background: Diabetes mellitus is the most common metabolic disorder all over the world. Though type 2 diabetes mellitus commonly occurs in subjects who are obese and insulin resistant, obesity defined by body mass index (BMI) is not a common feature in developing countries like India (only about 30%) as compared to developed countries (60% ? 80%) and rather a substantial number of these non obese were actually of low body weight or ?Lean? (BMI<18.5). Aim and objectives : To evaluate the microvascular complications in lean type 2 DM with special reference to glycemic and lipid profile ,and to compare it with normal body weight, overweight and obese type 2 diabetes mellitus . Materials and Methods: 74 Type 2 DM patients were divided into four groups according to BMI . Group I(Lean). Group II (normal Body Weight),Group III(Over weight),and Group IV(Obese) Results: Among the micro vascular complications, the Neuropathy was significantly higher (75%) in Lean than other groups. The Lean group had a lower prevalence of Retinopathy (40%) and Nephropathy(5%). A significantly severe hyperglycaemia was noted in the Lean group as compared to other groups in both the fasting state as well as the 2 hour post-prandial state. The total cholesterol in the Lean and the Normal Body Weight group was significantly lower than that of the Overweight group. Lean group had significantly lower triglyceride level as compared to Obese group. Triglyceride level increased significantly as BMI increases. Conclusion: Lean type 2 DM had more severe hyperglycaemia, higher risk of neuropathy, but had a patient friendly lipid profile .Further epidemiological studies with large number of patients are needed to look specially for complications as well as the genetic, immunological and hormonal status to find out the aetiopathogenesis leading to development of Lean type 2 diabetes mellitus .