Cysteine-rich secretory proteins (CRISPs) have been identified in diverse organisms, including epididymis, salivary glands, and snake venom. There is no report to show physiological function of CRISPs. We investigated the role of CRISP from Naja atra (CRISP-a) in inflammatory reponses of endothelial cells (ECs). CRISP-a induced the expression of adhesion molecule intercellular adhesion molecule-1 (ICAM-1), vascular adhesion molecule-1 (VCAM-1), and E-selectin, and chemokine growth related oncogene- (GRO-), in human umbilical vein ECs in a dose- and time-dependent manner. Treatment of ECs with CRISP-a induced phosphorylations of extracellular signal-regulated kinase (ERK), c-Jun-NH2-terminal kinase (JNK), and p38, and nuclear factor-B (NF-B)-DNA binding activity in ECs. Pre-treatment of ECs with heparinase, an enzyme that cleaves sulphational sites of heparan sulphate on the EC surface, inhibited the CRISP-a-induced GRO- expression, suggesting that heparan sulfur on the EC surface plays significant roles in mediating EC responses to CRISP-a. Our findings elucidate a mechanism by which CRISP from snake venom induces adhesion molecule expression in ECs, thereby playing inflammatory roles in vascular biology.