To investigate the influence of glucocorticosteroids on the coagulation system, some coagulation tests were performed before, after 2 days’ and after 6 weeks’ treatment with Prednisone® in 23 patients with collagen or hematological diseases. The prothrombin and proconvertin (P&P), plasma antithrombin III (AT-III), and factor VIII related antigen increased significantly, while the activated partial thromboplastin time (APTT), fibrinogen and plasminogen decreased significantly upon Prednisone treatment. Investigations on fibrinolysis were inconclu