Arginine kinase (ATP: arginine N-phosphotransferase, AK) in invertebrates catalyzes the reversible phosphorylation of arginine by MgATP to form phosphoarginine and MgADP. The conventional view is that phosphoarginine functions as ATP buffers, permitting maintenance of high ATP values during periods in burst of cellular activity in invertebrates. In this paper, the open reading frame (ORF) was cloned from shrimp, Litopenaeus vannamei, based on the fulllength cDNA sequence that was obtained in our previous study. The ORF encoding 356 amino acids of AK was cloned and inserted to a prokaryotic expression vector pGEX-4T-2. The recombinant protein was expressed as glutathione S-transferase (GST) arginine kinase (GST-AK) fusion protein, which was purified by affinity chromatography using Glutathione Sepharose 4B. The anti-AK polyclonal antibody was prepared by immunization of mice using this purified AK protein. The specific recognition of anti-AK antibody was further verified. The AK protein expression in various tissues was then analyzed using this newly prepared antibody by Western-blotting. The results revealed a strong expression of AK in heart, nerve, hemocyte, stomach and muscle, weak expression in eyestalk, hepatopancrease, gill and skin. The present study may be very useful for studying the function of AK in shrimp.