We characterized a specific binding site for pancreatic-type phospholipase A2 (PLA2-I) in several tissues and cells. The PLA2-I binding protein was purified from bovine corpus luteum membranes, which had a mass of 190 kDa. The purified protein, which possessed a binding capacity with high affinity and specificity for a mammalian mature type of PLA2-I, was a glycoprotein having a core protein of approx. 150 kDa and its carbohydrate moieties might be required for ligand recognition. PLA2-I elicited several biological responses in tissues and cells; i.e., cell proliferation and eicosanoid production, possibly through its specific binding site.