Anticoagulation is recommended for prophylaxis and treatment of venous thromboembolism (VTE) (deep vein thrombosis and pulmonary embolism) and/or arterial thromboembolism. The therapeutic arsenal of anticoagulants available to clinicians is mainly composed by unfractionated heparin (UFH), low-molecular-weight heparin (LMWH), fondaparinux and oral vitamin K antagonists (VKA) (i.e. warfarin and acenocumarol). These anticoagulants are effective, but they require parenteral administration (UFH, LMWH, fondaparinux) and/or frequent anticoagulant monitoring (intravenous UFH, oral VKA). Novel anticoagulants in clinical testing include orally active direct factor II inhibitors [dabigatran etexilate (BIBR 1048), AZD0837)], parenteral direct factor II inhibitors (flovagatran sodium), orally active direct factor X inhibitors [rivaroxaban (BAY 59-7939), apixaban, betrixaban, YM150, DU-176b, LY-517717, GW813893, TAK-442, PD 0348292] and new parenteral FXa inhibitors [idraparinux, idrabiotaparinux (biotinilated idraparinux; SSR 126517), ultralow- molecular-weight heparins (ULMWH: AVE5026, RO-14)]. These new compounds have the potential to complement heparins and fondaparinux for short-term anticoagulation and/or to replace VKA for long-term anticoagulation in most patients. Dabigatran and rivaroxaban have been the firsts of the new oral anticoagulants to be licensed for the prevention of VTE after hip and knee replacement surgery. In the present review, we discuss the pharmacology of new anticoagulants, the key points necessary for interpreting the results of studies on VTE prophylaxis and treatment, the results of clinical trials testing these new compounds and their potential advantages and drawbacks over existing therapies.