We examined autopsy reports and the clinical diagnoses of 600 patients (200 in 1967 and 400 in 1987). For each patient we considered age, diagnostic error, main diseases and presence of multiple pathology. The number of diagnostic errors increased from 1967 to 1987. The diagnostic error was particularly high for pulmonary embolism and septic shock and significantly higher in patients > 65 than < or = 65 years old. Multiple pathology was higher in old patients: we found 4 or more diseases in 195/270 (72.2%) patients > 65 years and in only 135/330 (40.9%) patients < or = 65 years. The average period of hospitalization was directly proportional to the number of diseases present in the same patient.