Trypsin, thrombin, fibrinolysin, papain, chymothrypsin and urokinase were immobilized on aminopolystyrene resin by the reaction of diazocoupling. An activation of prothrombin and plasminogen and also hydrolysis of fibrin by immobilized enzymes were studied. The immobilized enzymes hydrolyzed N-benzoyl-1-arginine ethyl ester and L-tyrosine ethyl ester. The only preparation of immobilized thrombin possessed the coagulational activity. After the covalent binding trypsin and plasmin maintained the capacity to cause a fibrinolysis. Immobilized trypsin, plasmin, papain, chymotrypsin and urokinase exhibited the fibrinolytic effect due to convertion of plasminogen into plasmin.