The accuracy of the clinical diagnoses compared to the findings of an autopsy is a more relevant characteristic of the quality of care than the length of stay in the hospital or the daily costs of the stay. The aim of this retrospective study was: a) to compare the clinical and pathological diagnoses, b) to determine the amount of new information supplied by the autopsy and c) to determine wether the knowledge of correct clinical diagnosis would have resulted in a change of therapy. At the medical ICU 163 patients died during 1998, autopsy was performed in 110 cases. Agreement of clinical and pathological diagnoses and causes of death were retrospectively assessed by a board. Acute myocardial infarction accounted for 26% of deaths, pneumonia and respiratory insufficiency for 15%, cardiac failure for 14%, sepsis for 14%, stroke for 13%, pulmonary embolism for 5% and others for 13%. The accuracy of the clinical cause of death was proved in 81% of the cases. The main disease was diagnosed correctly in 86% of the cases. As a tool in quality control, the agreement of clinical and pathological diagnoses and causes of death proved to be good during the examined period of time.