The Medical Research Council's Glomerulonephritis Registry was used to study clinicopathological correlations and renal survival in patients with IgA nephropathy reported between 1978 and 1985. IgA nephropathy was the histological diagnosis in 9.3 per cent of all renal biopsies reported to the registry during this period, and in 18.1 per cent of those with a primary glomerulonephritis. The 10-year cumulative renal survival rate accounting for censored data (Kaplan-Meier) was 83.3 per cent. Univariate analysis of survival curves (log-rank test) found the following parameters to be significantly correlated with poor renal survival: serum creatinine > 120 mumol/l (p < 0.001), hypertension (p < 0.001), serum albumin < 40 g/l (p < 0.005), proteinuria > 1 g (p < 0.025), age > 30 years (p < 0.025), and focal mesangial proliferation (p < 0.05). There was no significant difference in renal survival between males and females. Multivariate analysis (Cox's proportional hazards model) revealed that only a serum creatinine of > 120 mumol/l and a serum albumin of < 40 g/l were independently predictive of outcome. These findings indicate marked similarities between the UK experience of IgA nephropathy and the published European experience. IgA nephropathy is not a benign condition in the UK and patients with impaired renal function and/or those with a reduced serum albumin are significantly more likely to progress to end-stage renal failure within 10 years.