Background and Objective: Different pharmaceutical types of metformin are available for glycemic control in type 2 diabetes mellitus. There is some doubt about the efficacy of metformin produced by domestic pharmaceutical companies. As a clinical trial, we compared the efficacy and complications of metformin produced by an Iranian company with metformin from a Canadian company in diabetic patients. Materials and Methods: Eighteen eligible women (age range: 32-62 years) with type 2 diabetes received metformin (500 mg twice a day) either from Iranian company or from Canadian company each for 6 weeks period in a randomized, double blind, crossover study. Fasting blood sugar (FBS), HbA1C, lipid profile (Chol, TG, HDL, and LDL), weight, and BMI were assessed before and after each treatment phase. The results were compared with each other by paired sample T-test and Independent sample T-test. Results: Each of the two pharmaceutical types of metformin had the same therapeutic effects on FBS, HbA1C, lipid profile (except for HDL) and BMI. In addition, there was no significant difference between them in side effects (22.2% in each group). Conclusion: According to the beneficial therapeutic effects of Iranian metformin, lower side effects and low cost, in comparison to its Canadian type, it seems that using Iranian metformin would be a suitable choice for control of glycemic patients. However, in this regard, further studies with greater samples are recommended.