The chemistry, pharmacokinetics, pharmacodynamics, clinical efficacy, dosage and administration, adverse effects, and therapeutic role of tinzaparin are reviewed. Tinzaparin is a low-molecular-weight heparin (LMWH) with antithrombotic properties. It has FDA-approved labeling for use in the treatment of acute symptomatic deep-vein thrombosis (DVT) with or without pulmonary embolism (PE) when administered in conjunction with warfarin sodium. Tinzaparin works by inhibiting reactions that lead to the clotting of blood. The much-improved pharmacokinetics of tinzaparin compared with unfractionated heparin (UFH) are due to its lower affinity for heparin-binding proteins and endothelial cells, shorter fractionated heparin chain (which allows for better bioavailability), and unsaturable renal elimination. Clinical trials have demonstrated that tinzaparin is at least as safe and effective as UFH for the treatment of DVT. Tinzaparin may also be effective for unlabeled uses, such as prophylaxis of venous thromboembolism (VTE) after orthopedic, general, and abdominal surgery, although more data are needed to define the optimal dose for this indication. The recommended dosage of tinzaparin for the treatment of established DVT with or without PE is 175 anti-factor Xa IU per kilogram of body weight administered subcutaneously once daily for at least six days until the patient achieves adequate anticoagulation with warfarin. As with other LMWHs, the most common complication of tinzaparin therapy is bleeding. Tinzaparin offers an additional treatment option for VTE.