A hospital-based case-control study was carried out to investigate the association between ANCA positive rapidly progressive glomerulonephritis (RPGN) and occupational exposure to silica dust. All ANCA positive male patients admitted to the Department of Nephrology of the University of Brescia between 1987 and 1992 were enrolled in the study as cases. The controls were pts of the same age, admitted at the Department immediately before or after the cases, affected by other renal diseases. Seven of the 16 cases and one of the 32 controls, had a positive history for jobs exposing to silica dust (relative risk 14; 95% C.I.: 1.7-113.8, p < 0.001). ANCA pattern was p-ANCA with anti-MPO antibodies in 6/7 of exposed pts. The review of renal histology showed a distinctive glomerular lesion consisting in peripheral nodular areas of glomerular sclerosis, in addition to the crescentic necrotizing glomerulonephritis, in 3/6 silica exposed pts, but in none of the unexposed pts.