The search for a cancer is part of the classical investigation of unexplained venous thrombosis. Arterial thrombosis associated with neoplasia is more rare. The authors report two cases in which arterial thrombosis was the final event of their malignant disease. The first case had abacterial thrombotic endocarditis and disseminated intravascular coagulation at the origin of multiple thrombotic complications. The initially unknown cancer was a pancreatic adenocarcinoma. The second case presented with acute occlusion of the iliac artery after ablation of a malignant melanoma. Despite embolectomy with a Fogarty catheter and effective anticoagulation, the thrombosis recurred several times at the same site. The clinical features and the mechanisms of these two cases suggestive of Trousseau's syndrome are discussed.