Behcet's disease is a multisystemic disease of unknown etiology. Disease manifestations consist of recurrent oral and genital ulceration, skin lesions, and relapsing ocular inflammation. Arterial involvement is an uncommon complication of Behcet's disease, and it most frequently affects the abdominal aorta followed by femoral artery, and the pulmonary artery. Coronary lesions in Behcet's disease have been little reported in the literature. A-36-year-old female with 6-year history of Behcet's disease was hospitalized with ectasia of the left main coronary artery. This unusual vascular complication Behcet's disease is presented.