Twenty-two patients with crescentic anti-GBM nephritis or Goodpasture's syndrome with renal impairment were reviewed. All patients were treated with a combination of plasma exchange and immunosuppression. Sixteen patients (73 per cent) showed improvement in renal function (greater than 30 per cent reduction in serum creatinine level) apparently in response to treatment, and nine patients (41 per cent) made long-term recoveries in renal function. The most important features carrying a bad prognosis were total anuria, and/or a very high percentage of glomeruli showing crescents (greater than 85 per cent) in the initial renal biopsy. Some patients with other so-called 'bad' prognostic features, including severely impaired renal function at presentation, oliguria and the need to institute dialysis had unexpected marked improvement in renal function and/or recovered renal function in the long term provided treatment with plasma exchange was begun promptly and maintained for a sufficient period to allow resolution of the disease process. Renal biopsies at the beginning and later proved to be an extremely valuable guide for the progress and outcome of the disease.