Aim:In glioblastoma multiforme, the balance between the procoagulant system, anticoagulant system and fibrinolytic system is impaired in favour of hypercoagulability. The aim of this study was to compare glioblastoma multiforme with astrocytoma grade II by subjectively evaluating the levels of prothrombin and biotinylation thrombin, and G protein serum protease activatin receptors, as tissue factors causing hypercoagulation and affecting coagulation. Material and Methods:Specimens from 35 cases with glioblastoma multiforme and 23 cases with astrocytoma grade II were evaluated immunohistochemically. The specimens were stained with hematoxylen-eosin and immunohistochemically for prothrombin, biotinylation thrombin and protease activating factor receptors to determine the correlation between the tumor malignancy and coagulation factor receptors. Results:An increase in malignancy was seen to result in an increase in prothrombin, biotinylation thrombin, protein activator receptor 1, protein activator receptor 3, and protein activator receptor 4 levels, and a decrease in protein activator receptor 2 level. These data showedthat there was hypercoagulability in glioblastoma multiforme. Descriptive statistics and Mann-Whitney U analysis were used to evaluate the results. Conclusion:In glioblastoma multiforme, if there is no radiologicalevidence of hemorrhage, low molecular weight heparin should be administered peroperatively and continued for 3 months postoperatively to prevent the development of deep venous thrombosis. This will also be useful in the prevention of invasion, angiogenesis, metastasis and tumour progression.