Twenty cases of pre-eclamptic toxemia were examined clinicopathologically. Twelve primipara and 6 multipara underwent renal biopsy at 1-24 (3.5 +/- 5.4, mean +/- SD) weeks after delivery. Specimens were examined by light and electron microscopy and immunofluorescence. Their mean blood pressure at delivery was 177.0 +/- 19.4/116.3 +/- 10.2 mmHg, proteinuria was 9.5 +/- 8.4 g/day. Follow-up period was 23.0 +/- 19.3 months after delivery. The severity of double contour of the glomerular basement membrane and mesangial interposition were correlated with the amount of proteinuria at biopsy (r = 0.40, p less than 0.05, r = 0.51, p less than 0.05, respectively). Proteinuria disappeared in all cases after delivery. The length of the hypertensive period after delivery correlated with the severity of glomerular lesions (r = 0.63, p less than 0.05), but did not correlated with the severity of vascular lesions. All patients became normotensive within three months after delivery. No patients showed microhematuria during pregnancy or after delivery.