Patients with cancer have long been an important and enigmatic part of basic science and clinical research in thromboembolic disease. The reciprocal deleterious effects on outcomes of a cancer diagnosis on patients with thrombosis and a thrombotic event on patients with cancer have been observed and documented for more than a century. Patients with cancer continue to be one of the more difficult populations to manage using the available unfractionated and low-molecular-weight heparins and the oral vitamin K antagonists. High rates of failure and bleeding complications have made researchers and practitioners alike seek newer more effective anticoagulation agents. The novel oral direct thrombin and activated factor Xa inhibitors have been shown in large clinical trials to be safe and efficacious in many prophylaxis and treatment settings. However, practitioners who treat patients with cancer should be cautious using these agents until more studies are specifically performed in this thrombophilic patient population.