Dalteparin is a low molecular weight heparin (LMWH) with a mean molecular weight of approximately 5,000. As with the other low molecular weight heparins, dalteparin has certain advantages over unfractionated heparin (UFH) most important of which are improved bio-availability by subcutaneous injection, a prolonged antithrombotic activity which is highly correlated with body weight permitting the once daily administration of the drug. Other possible advantages of LMWH including dalteparin include a lower incidence of heparin induced thrombocytopenia and thrombosis and decreased tendency to produce osteopenia on prolonged administration. Dalteparin has been subjected to a large number of well designed randomised clinical trials for the prevention and treatment of venous thromboembolism. Based on data from the randomised clinical trials, dalteparin has been approved internationally for a wide spectrum of clinical indications.