In May 1981, a massive intoxication of people who had ingested adulterated cooking oil took place in Madrid and nearby provinces. Although the patients presented, in the first phase of the disease, with acute respiratory illness, later on thromboembolic complications, severe neuromuscular involvement, and scleroderma-like cutaneous lesions appeared. Kidneys were apparently spared; however, 4 out of 842 admitted patients developed glomerulonephritis; kidney biopsies revealed glomerular, vascular, tubular, and interstitial changes. Cases 1 and 3 had diffuse proliferative endocapillary glomerulonephritis; case 2 had diffuse membranoproliferative glomerulonephritis; and case 4 had diffuse extracapillary glomerulonephritis. Three cases had vascular lesions characterized by degenerative and proliferative endothelial changes, intimal foamy macrophages, and partial or complete obliteration of the vascular lumen by concentric myxoid fibrosis. There were signs of necrosis of tubular epithelium along with edema and lymphocytic and eosinophilic interstitial infiltration. Two out of 22 autopsies had segmentary glomerulonephritis, and 17 out of 22 autopsies showed renal vascular lesions.