Background: Polycystic ovary syndrome (PCOS) is the most common and prevalent endocrinopathy in women, and the most common cause of anovulatory infertility. An altered lipid profile is common in polycystic ovary syndrome (PCOS) and is usually characterized by increased total cholesterol, triglycerides, low-density lipoproteins and very low density lipoprotein levels with low high-density lipoprotein. PCOS is associated with a higher frequency of cardiovascular disease because of dyslipidemia. Which are potent markers for cardiovascular risk factors. Metformin, is a widely used antihyperglycemic agent. It decreases insulin resistance and reduces hyperglycemia through a reduction of the hepatic glucose production. Objectives: Determine the beneficial effect of metformin in PCOS patients in reducing lipid profile and subsequently reduction in cardiovascular disease. Method: Measurements and analysis levels of total cholesterol, triglycerides, low-density lipoproteins, very low density lipoprotein and high-density lipoprotein were samples collected at the Institute of embryo research and infertility treatment, Al-Nahrain University. PCOS patients were recruited at the consultant clinic Patients: forty three women with PCOS were studied. Anthropometric data, lipid profile, were evaluated, before oral metformin (500mg/twice daily) treatment and after three months of use. Results: Patients with PCOS after oral metformin treatment, revealed a significant lowering serum concentrations of total cholesterol, triglyceride, low-density lipoproteins and very low density lipoprotein and elevated high-density lipoprotein compared to before treatment. Conclusions: dyslipidemia is common finding in PCOS women, in this study we found that the use of oral metformin tablets 500mg/twice daily for three months will correct lipid profile level (cholesterol, triglyceride, LDL, VLDL and HDL) which is considered as cardiovascular risk factors and this lead to reduce risk of cardiovascular diseases.