To determine whether advances in diagnostic procedures have reduced the value of autopsies, we analyzed 100 randomly selected autopsies from each of the academic years 1960, 1970, and 1980 at one university teaching hospital. In all three eras about 10 per cent of the autopsies revealed a major diagnosis that, if known before death, might have led to a change in therapy and prolonged survival; another 12 per cent showed a clinically missed major diagnosis for which treatment would not have been changed. Among 1980 autopsies, renal disease and pulmonary embolus were less common causes of death than before, but systemic bacterial, viral, and fungal infections increased significantly and were missed clinically 24 per cent of the time. The introduction of radionuclide scans, ultrasound, and computerized tomography as diagnostic procedures did not reduce the use of conventional tests in patients who subsequently died and were studied by autopsy. Over-reliance on these new procedures occasionally contributed directly to missed major diagnoses. We conclude that advances in diagnostic technology have not reduced the value of the autopsy, and that a goal-directed autopsy remains a vital component in the assurance of good medical care.