The morphologic classification and clinical spectrum of 1,001 cases of primary glomerulonephritis (GN) in Jinling Hospital during 1980-1988 were analysed. It was found that the incidence of mesangial type lesion including mesangial proliferative GN, IgA nephropathy and IgM nephropathy ranks first (21.5%, 32.1% and 10.1% respectively), which is not only the commonest cause of patients clinically manifesting nephrotic syndrome and gross hematuria but also the predominant type of nephritis causing uremia and hypertension.