Polycystic ovary syndrome (PCOS) is a common disorder in female during reproductive age , it's incidence is (5-10%). It is a common cause of female infertility, hirsutism , menstrual abnormalities , obesity and even it may, cause endomaterial cancer, cardiovascular disorder and diabetes mellitus. Yet its etiology is unknown , and a lot of studies are doing on . The hormonal changes are complicated and the diagnostic criteria are not very specific. Clomiphene citrate (CC) is the first choice of treatment for infertility of PCOS . The present study was designed to investigate changes in the levels of hormones , leptin and trace elements in the serum of untreated group of PCOS , treated group (with CC) and the control group. Serum collected from 42 patients of PCOS and 20 control (age matched). Serum levels concentration of hormones : lutineizing hormone ( LH ), follicle stimulating hormone ( FSH ), prolactin (PRL.) , progesterone ( Prog.) and testosterone ( Testo.) were assessed by using radioimmunoassay ( RIA ). High performance liquid chromatography (HPLC) was employed in quantitation of leptin using C-18 DBS column ( 250 * 4.6 mm Id). The mobile phase for leptin was acetonitrile : distilled water (30:70 V/V) , flow rate Iml/min, detection at 257nm and separation temperature was at room temperature (21-25 °C).Serum levels concentration of trace elements : zinc (Zn ) and magnesium ( Mg) were assessed using flame atomic absorption spectrophotometry ( AAS ), while chromium ( Cr ) and selenium ( Se ) were analyzed using flameless atomic absorption spectrophotometry.