For many years, available anticoagulant medications were limited to vitamin K antagonists, unfractionated heparin, and aspirin. However, in the past 20 years, several new agents have been developed for the treatment of thrombosis, and even more are being developed. This increasing number of medications has led to more specific treatment algorithms for the care of venous and arterial thrombotic events. As more agents become available, treatment guidelines are rapidly changing. With increasing frequency, interventional radiologists encounter patients already taking anticoagulant medications prophylactically or therapeutically, or they need to determine which anticoagulant medications need to be initiated for a particular procedure. Therefore, it has become increasingly important to understand the mechanisms, risks, and benefits of anticoagulant medications. A review of the traditional anticoagulants, their new counterparts, and their places in the medication repertoire of interventional radiology will be discussed herein.