Polycystic ovary syndrome (PCOS) is one of the most common Metabolic and reproductive disorders affecting women during their Reproductive period. PCOS patients have increased platelet aggregation and Decreased fbrinolytic activity. Decorin (DCN) increases platelets activation And fibrinolytic activity .aim of the study: to investigate the effect of decorin On hemostasis in PCO rat model. Material and methods: Thirty virgin Adolescent female rats were divided in two groups control (group I) and PCO Induced group II (PCOS induced by single IM of estradiol valerate). This Group was further subdivided into two equal subgroup: Subgroup Iia (PCO Induced group). Subgroup Iib(DCN” 60 ug/kg” treated PCO group).in all Groups, serum sex hormones, Bleeding time (BT), whole blood clotting time (WBCT), prothrombin time (PT), activated partial thromboplastin time (aPTT), INR, D-dimer (DD), ovarian oxidative stress markers and STAR, 3β-HSD, CYP 19A1, plasminogen activator inhibitor 1 (PAI-1) gene Expression were estimated. Results: statistically significant prothrombotic State in the PCOS control group, as reflected by decreased bleeding, whole Bood clotting times, PT, aPTT, INR and CYP 19A1 m RNA expression Together with significant increases in D-dim ers (DD, tissue PAI, 1 STAR, 3β-HSD and PAI-1 m RNA, however, in DCN treated PCO group there was A significant increase In WBCT, PT, aPTT, INR, superoxide dismutase (SOD), CYP 19A1 m RNA expression, accompanied by a Significant decrease in DD, clot retraction, and Malonaldehyde (MDA), 1 STAR, 3β-HSD, PAI1 gene expression In comparison To PCO control. Conclusion: Decorin can improve hemostatic Profile In PCO rat model