Background/aim: India has 63 million diabetic people and the overall prevalence of diabetes in this country is 8.37%. Lifestyle modification by education is the most cost-effective strategy to have better metabolic control. The aim of this study was to investigate the effects of a self-management educational program on control of type 2 diabetes Materials and methods: It was a randomized controlled interventional study conducted among 306 patients with type 2 diabetes mellitus attending the Diabetic Clinic at G.T.B. Hospital, Delhi, from March 2010 to May 2013. The intervention was in the form of group education based on a self-management program, which was earlier developed in the pilot study. Results: The baseline characteristics were comparable in the two groups. After 6 months, there was a significant improvement in the HbA1c levels (P = 0.0001), physical activity level (P = 0.001), and BMI (P = 0.001) in the study group as compared to the control group and this difference persisted even when analysis was done using generalized estimation equations. Conclusion: The findings of this study proved that a self-management educational program is an essential component in the management of diabetes and provided concrete evidence that this is an effective instrument in the control of body weight, blood pressure, and glycated Hb levels in type 2 diabetes.