Although coagulatory system disorders are well recognized in patients with acute leukemia, these usually present with either hemorrhagic complications or thrombosis of small vessels. Large vessel thrombosis is a very rare clinical presentation. We present a patient with previously undiagnosed acute myeloid leukemia (M5), who was referred to our hospital with symptoms of acute ischemia of his right lower limb. Occlusion of the right external iliac artery due to a combination of leucostasis and coagulation disorders was noted and successfully treated with urgent leukapheresis, immediate chemotherapy and surgical thromboembolectomy.