IgG- and C3b-coated erythrocytes were used to investigate splenic Fc-receptor function and hepatic C3b-receptor function by measurements of their blood clearance. Most patients with glomerular disease including those who were HLA, Al, B8, DR3 had normal Fc-receptor function. Occasional individuals with persistent glomerulonephritis had delayed clearance unrelated to disease activity. In rapidly progressive glomerulonephritis, the phenomenon of ‘reticulo-endothelial blockade’ was confirmed. C3b-receptor function was normal in most patients with persistent glomerulonephritis. A defect in splenic Fc-receptor function hepatic C3b-receptor function is unlikely to underlie persistent glomerulonephritis.