Abstract: Novel human protein C derivatives are described. These derivatives have increased anti-coagulation activity, resistance to serpin inactivation, and increased sensitivity to thrombin activation compared to wild-type protein C and retain the biological activity of the wild-type human protein C. These derivatives will require either less frequent administration and/or smaller dosage than wild-type human protein C in the treatment of acute coronary syndromes, vascular occlusive disorders, hypercoagulable states, thrombotic disorders and disease states predisposing to thrombosis.