This report describes three patients treated for acute arterial thrombosis due to malignancy-related hypercoagulability (Trousseau's syndrome). The average age was 59 yr. There were two women and one man. The cancers were breast, lung, and pancreas. Atherosclerosis or nonneoplastic hypercoagulable states did not appear to be a factor in any patient. One patient who presented with irreversible arm ischemia and Stage IV breast cancer underwent primary amputation. The other two patients underwent immediate surgical thrombectomy and thrombolytic therapy, and malignancy was discovered during postoperative workup for hypercoagulable states. Both ultimately required amputation. All three patients died due to cancer less than one year after presentation. When a hypercoagulable state is suspected as the cause of acute arterial thrombosis, an evaluation for occult malignancy is indicated. Although aggressive revascularization attempts may be appropriate, the prognosis for limb salvage and long-term survival is poor.