Abstract: Objective To investigate the clinical significance of the changes of angiotensionⅡ (AngⅡ) in children with IgA nephropathy (IgAN). Methods Thirty children diagnosed as primary IgA nephropathy by renal biopsy (IgAN group) and 30 healthy children (control group) were recruited from May 2008 to December 2012. The serum and urine AngⅡ were measured by ELISA and compared between IgAN group and control group. The AngⅡ expression in the renal tissue of IgAN group was detected by immuno-histochemical method, and was correlated with other clinical data.. Results Urine AngⅡ was significantly higher in the primary IgAN group than that of control group (P < 0.05); AngⅡ expression in the urine is positively correlated with proteinuria (r=0.37, P=0.046), and is associated with the severity of clinical presentation; AngⅡ expression in kidney tissue increased with the severity of the renal histopathologic grading (r=0.69, 0.79, P=0.000), while AngⅡ in blood and proteinuria, AngⅡ expression in kidney tissue were not significantly correlated with the number of crescents. Conclusions Urine AngⅡ in children with IgAN is significantly correlated with the severity of the pathologic stage and the level of proteinuria. Urine AngⅡdetection may be useful to assess the progress and prognosis of chronic kidney disease.