A case of coumadin necrosis of the breast is presented. Most patients with this entity are obese, middle-aged females who have been treated with oral anticoagulants for three to five days for thrombophlebitis or peripheral arterial embolization. The key to therapy is early diagnosis and clinical differentiation from subcutaneous hemorrhage--a disease which is self-limited, nonprogressive, and treatable when anticoagulant therapy is either discontinued or reversed with vitamin K. Surgical debridement or simple mastectomy is generally necessary in those cases where necrosis is present.