Objective: The aim of our study was to find out the amalgamated and comparative synergetic effects of metformin and black coffee in type 2 diabetes mellitus treatment. Study Design: An experimental, randomized control study. Place and Duration: This study was conducted at Pharmacology laboratory and Multidisciplinary laboratory of Services hospital Lahore for the duration of one year starting from November, 2019 to October, 2020. Methodology: In our study we enrolled 50 male weighing 30-50 g albino Balb/c mice. Group 1 was consisting on non-diabetic normal control (n=10) and diabetes was induced in experimental group (n=40) by using low dose streptozotocin (40mg/kg). We further divide diabetic mice into 4 groups (10 mice/group). Group 2 consist on diabetic controls and the remaining three groups treated with metformin, black coffee and combination of both for 45 days. We use intracardiac puncture method to took blood samples for HbA1c. SPSS version 20 were used for the statistical analysis of data. With the use of one-way ANOVA (post hoc Tuckey test), comparisons of HbA1c among different groups were analyzed. (P-value <0.05) Results: According to the results of our study we noticed that metformin treated (Group 4), black coffee treated (Group 3) and combination of black coffee and metformin treated (Group 5) had decreased the level of serum HbA1c in comparison with those who found in diabetic control (Group 2). (P<0.05) Conclusion: At the end of our study, we conclude that combination of metformin and black coffee decrease the level of serum of HbA1c in diabetic mice as compared to separately use of black coffee and metformin. Key Words: HbA1c, Diabetes Mellitus, Pancreatic Islets, Cells Metformin