Anticoagulant drugs are of crucial importance for the treatment and prophylaxis of thrombotic disorders. The use of traditional anticoagulants like heparin and warfarin is majorly associated with bleeding complications. In the quest for safer anticoagulation therapy, the interest for the isolation of novel anticoagulant compounds has shifted towards natural sources. Peptides can be considered as better alternative due to their therapeutic potential in the treatment of diseases. Peptides from hematophagous (blood-feeding) and venomous organisms have been recognized as potential anticoagulant agents. Of late, peptides derived from the hydrolysis of food proteins, including edible seaweeds, milk and seed proteins, have also shown to possess promising in vitro anticoagulant activity. To overcome the problems associated with regular anticoagulants, peptides targeting vital steps in the clotting cascade have been studied. This review focuses on anticoagulant peptides with known targets, inhibiting crucial factors in the coagulation cascade such as FXa, FXIa, FXIIa and FVIIa/TF complex, as well as peptides with unknown targets. © 2018, Springer Science+Business Media, LLC, part of Springer Nature.