Male infertility and issues of impaired fecundity have been currently a global problem. Diabetes mellitus can influence male fertility either directly or indirectly due to abnormal spermatogenesis, which results in reduced sperm quality. Most reported cases of diabetes are of type 2 DM cases, frequently treated with oral anti-diabetic drugs. Metformin is considered first-line therapy for the treatment of T2DM. This drug is an oral insulin-sensitizing agent that can elevate insulin sensitivity and reduce plasma fasting insulin. The main metabolic action of metformin target the liver. However, it was indicated that metformin acts on many organs of the body which include the male reproductive system. With the increasing numbers of diabetic individuals among younger people, there is an enhancement in the utilizaton of metformin in individuals of this age group. Therefore, it is critical to recognize the role of metformin in male fertility. In this review, we are presented with the most recent data accessible regarding the investigation of the influences of metformin on the male reproductive system. Together with the discussion of these influences, their importance to male fertility is also argued.