The introduction in Japan of routine urinalysis for pre-school and school age children has greatly facilitated the discovery of renal disease in asymptomatic children. Over the past 8 years at Kitasato University Hospital, we have studied 113 cases of chronic progressive renal disease based on renal biopsy. Thirty-one of these 113 patients were found by routine urinalysis at area schools. It is note-worthy that many of the asymptomatic children were found to have renal diseases such as MPGN, FGS, and IgA nephropathy. Although it is difficult to decide whether or not medical management is required for asymptomatic children, the histological findings may give pertinent guidance for planning an appropriate therapeutic program in the early stages of various types of renal disease. This early detection may enable us to observe these potentially progressive renal diseases from the early phase and to provide clues for the investigation of the pathogenesis of these renal diseases.