SummaryPreliminary report of the results obtained with an indirect immunofluorescent technique applied to the study of renal biopsy specimens.Depositions of IgG, IgA, IgM, complement, fibrinogen and albumin were investigated in glomeruli of children with diffuse nephropathies and in adult controls. The localization of the protein precipitates was confirmed by comparing the immunofluorescent picture with the results of the P.A.S.M./ H.E. staining of the same sections.