The experience acquired in an anticoagulation clinic during 4 1/2 years is reviewed to demonstrate the effectiveness of such a clinic and to provide the practicing physician with guidelines for managing outpatient oral anticoagulation therapy. The experience is based on anticoagulant therapy in 141 patients during 1,264 patient-months. The patient population is characterized and aspects of management are explored, such as the incidence of major and minor complications (5% and 18% per treatment course, respectively), failure rate, and adequacy of therapy control. Guidelines concerning patient education, prothrombin time control, and other management suggestions are also given. This study, which compares favorably with others, is intended to aid the practicing physician and improve management of outpatient anticoagulation therapy.