The renin-angiotensin system plays key roles in the regulation of blood pressure and electrolyte,and body fluid dynamics.Recently,big angiotensin-25(Bang-25),which consists of the angiotensinogen sequence(1-25)having the N-linked complex-type nonasaccharide on Asn14 and cystine structure on Cys18,has been isolated from human urine by Kitamura et al.[1] In this study,we have synthesized Bang-25 not only to confirm its reported primary structure including the N-linked oligosaccharide but also to obtain it in much larger amounts than can be isolated from the natural sources for elucidating its physiological function.