Background: Lack of physical activity and high body mass index (BMI) is linked to the aggressiveness of prostate cancer due to alteration of circulating levels of metabolic and sex hormones with reduced glucose uptake that led to the development of insulin resistance.  Objective: evaluate the effect of adding metformin to the combined androgen-deprivation therapy (ADT) in metastatic cancer prostate patients. Patients and methods: Patients were included if having a diagnosis ofStage IV prostatic adenocarcinoma, No prior use of ADT, chemotherapy, and no prior use of metformin or other diabetes mellitus treatment. Both study groups received Combined ADT in the form of bilateral orchiectomy or luteinizing hormone-releasing hormone (LHRH) agonists; Goserelin 3.6 mg subcutaneous q28 days with Bicalutamide 50 mg PO daily. In the Trial arm, Metformin was administered as metformin 1000 mg/twice daily. Patients were monitored monthly for compliance, safety. Prostatic specific antigen (PSA) level, random blood glucose, body weight, and drug-related side effects were evaluated every 3 months Disease progression was evaluated every 6 months. Results: the addition of metformin to (ADT) in our study showed improvement of progression-free survival 39 months vs 30 months, PSA response at 9 months, and radiological response at 9 months were factors correlating with better PFS. There was an improvement in the quality-of-life assessment. Conclusion: metformin should be considered as an effective agent to be used in combination with standard treatments for prostate cancer. The present study showed that Metformin use was associated with improved PFS and OS.