The risk of hypercoagulability is increased when the hemostatic balance between procoagulant and anticoagulant mechanisms is shifted in favor of coagulation. Hypercoagulability is an increasingly recognized contributor to the deleterious manifestations of veterinary disease. The basis for thrombus formation in many acquired diseases is being investigated and more clearly defined. A thorough understanding of the hemostatic system and knowledge of disorders that lead to hypercoagulable states are critical to a logical therapeutic approach.