Abstract : The aim of this study was to investigate the effect of Prosopis cineraria leaves methanolic extract on platelet aggregation and whole blood coagulation in-vitro. In this study, Methanolic Extract of Prosopis cineraria (MEPC) leaves were extracted by using methanol to evaluate possible platelet aggregation activity, calcium induced whole blood coagulation, fibrinolytic activity, prothrombin time (PT) and activated partial thromboplastin time (APTT). Platelet aggregation activity was determined in vitro by Platelet Rich Plasma (PRP), APTT and PT was measured in-vitro by Platelet Poor Plasma (PPP) and calcium induced whole blood coagulation and fibrinolytic activity was determined on non-citrated whole blood. The results showed that MEPC has significant platelet aggregation activity in a dose dependent manner when used alone. It has efficacy to induce coagulation in whole blood by successively increasing the dose. In platelet independent coagulation, by using thromboplastin and partial cephaloplastin, no definitive results were obtained by MEPC.