C-type lectin-like proteins (CLPs) of snake venom have a variety of biological properties, acting for example as anticoagulants, procoagulants, and agonists / antagonists of platelet activation. The structural and functional studies of the first identified CLP, factor IX / factor X-binding protein, have led to an understanding how new functionally heterodimeric CLPs from monomeric C-type lectin related proteins may have evolved by 3D domain swapping, and have contributed to our understanding of the significance of magnesium ions in the blood coagulation cascade reaction. Two metallo-proteases, carinactivase and RVV-X (factor X activator of a snake venom), with C-type lectin-like domains, were isolated, characterized, and found to be useful in the study of the properties of prothrombin and coagulation factor X. There are also several unique CLPs belong to agonists and antagonists of platelet receptors, platelet glycoprotein Ib and glycoproteins Ia / IIa and VI, collagen receptors and the following CLPs that modulate platelet function. These CLPs may provide the new insights into platelet function: alboaggregin -B, echicetin, botrocetin, bitiscetin, flavocetin-A, aggretin / rhodocytin, convulxin, and agkistin.