Urokinase modification by substances, possessing their own therapeutic activity, permits to obtain preparations of combined action on the enzyme basis, the catalytic properties of the modified enzyme being similar to those of the native one. The coupling of sodium nitroprusside to urokinase makes the action of the vasodilator more prolonged. Urokinase modification by heparin produces stabilized preparations, possessing fibrinolytic and anticoagulative activity. Derivatives of manifold modified urokinase have been experimentally obtained. Urokinase-heparin-sodium nitroprusside conjugates simultaneously exhibit fibrinolytic, hypertensive and anticoagulative effect. Urokinase coupling to fibrinogen via aliphatic diamine "spacer group" increases the affinity of the modified enzyme derivative to thrombus material. This provides the increased local fibrinolytic activity of the obtained urokinase preparation. The method suggested point out the new possible ways of creating highly effective therapeutics.