Objectives Metformin is the first choice for type 2 diabetes mellitus (T2DM) treatment in the guidelines and is used in combination with many drugs. Growth arrest-specific protein 6 (Gas6)/Axl signaling plays a role in many metabolic disorders. This study aims to investigate the effects of metformin and metformin-insulin combination used in patients with T2DM on Gas6, Axl, and soluble Axl (sAxl) levels. Materials and methods A total of 71 patients diagnosed with T2DM and 21 healthy subjects were divided into 4 groups control, diet and exercises recommended (DER), metformin, and metformin + insulin. Diabetic patients were treated with metformin only or with a metformin-insulin combination and monitored for six months. Gas6, Axl, and sAxl levels of subjects' sera obtained from their baseline and post-therapeutic sixth month blood samples were measured by ELISA methods. Results Compared to baseline, the sixth month Gas6 and Axl levels of Metformin and Metformin + Insulin groups significantly decreased (p<0.05). However, there was no statistically significant difference in sAxl values for these two groups of patients. Discussion The use of metformin in diabetic patients may be beneficial for inhibiting the Gas6/Axl pathway. This study presents a new aspect of the pleiotropic effects of metformin. This study will be clinically useful for designing therapeutic approaches targeting Gas6/Axl.