Certificates of 1,454 deaths occurring over 11 months were retrieved from the Civil Register in Valencia, Spain. Relevant medical information was systematically gathered from hospital records, questionnaires, and Coroner reports. We compared the underlying cause of death (UCD) from the original death certificate, and a reference cause of death (RCD) determined by a panel of experts based on all available information. Overall, 80.2 percent of the certificates were concordant for disease category, but there was a great disparity among some specific disease categories.