Objective: Renal involvement is an important factor to determine the prognosis of HSP. The aim of this study was to elucidate the independent risk factors of renal involvement in children with Henoch-Schönlein purpura (HSP). Methods: We performed retrospective study of 488 patients who were diagnosed as HSP from February 1990 to January 2011 at Gyeongsang National University of Hospital. The evaluated clinical and laboratory features are as follows: age, gender, distribution and degree of purpura and angioedema, presence of gastrointestinal bleeding, severity of gastrointestinal involvement, central nervous system involvement, relapse frequency, steroid treatment, and endoscopic findings. Renal involvement was defined as presence of urinary abnormality (microscopic hematuria with/without proteinuria). The severity of renal involvement was determined by the most severe urinary abnormality during the follow up period. Results: Renal involvement was found in 169 patients (34.9%). Microscopic hematuria was found in 88 patients (18%) and microscopic hematuria with proteinuria was found in 81 patients (16.6%). Multivariate analysis revealed that age ( P0.01; OR=1.3; 95%CI 1.16-1.35), purpura on face or earlobe ( P0.01; OR=2.5: 95%CI 1.34-4.70), severe gastrointestinal involvement ( P0.01; OR 1.45; 95%CI 1.10-1.90) and frequent relapse ( P0.01; OR 1.73: 95%CI 1.29-2.33) increased the risk of renal involvement. Among them, degree of gastrointestinal involvement ( P0.01: OR 1.47: 95%CI 0.99-2.98) and relapse frequency ( P0.01; OR 1.75; 95%CI 1.35-2.26) were risk factors of severity of renal involvement. An extensive angioedema ( P0.01; OR 0.74; 95%CI 0.60-0.92) is a protective factor of severe renal involvement. Conclusion: older age, purpura on face or earlobe, severe gastrointestinal involvement and frequent relapse were independent factors of renal involvement in pediatric HSP. Severe gastrointestinal involvement and frequent relapse are risk factors of severe renal involvement, but extensive angioedema is a protective factor of severe renal involvement independently. We recommended that pediatric HPS patients who have those risk factors should be rigorously monitored.