Abstract : Introduction: Type 2 Diabetes mellitus is characterized by high blood glucose, insulin resistance, and relative lack of insulin. Common symptoms include increased thirst, frequent urination, and unexplained weight loss. Material and Methods: This is a Prospective, Comparative, Randomized and Parallel group study. Study was conducted in Type 2DM patients attending the outpatient department of Medicine in tertiary care center. Group I received Metformin 500 mg BD for 3 months, Group II received Sitagliptin 50 mg BD for 3 months and Group III Metformin 500 mg BD and Sitagliptin 50mg BD for 3 months. Result: The mean fasting blood glucose level in Group I at baseline was 143.14±5.38 mg/dl and after 3 months was 93.85 mg/dl, in Group II was 147.15 ±5.38 mg/dl and after 3 months 91.47±4.20 mg/dl and in Group III was 145.23±5.47 mg/dl and after 3 months 87.47±4.27 mg/dl. The mean of PPBG level in Group I was 194.23±14.58 mg/dl at baseline, followed by 152.68±9.24 mg/dl after 3rd month. In Group II the mean of PPBG level was 197.79±14.52 mg/dl at baseline followed by 131.47±8.63 mg/dl after 3rd month. In Group III the mean of PPBG level was 196.64±13.63 mg/dl at baseline followed by 127.74±9.37 mg/dl after 3rd month. Conclusion: Both sitagliptin or metformin monotherapy helped in improving glycemic control in patients with type 2 diabetes mellitus. Both the group of the drugs was well tolerated by the patients. The result of this study provides the data for the use of sitagliptin as initial monotherapy for type 2 diabetes mellitus patients.