Background: Death certificates are frequently used as the source for epidemiological data on the prevalence of diseases. We postulated that comorbidities may be under-documented, particularly in older patients with multiple coexisting conditions.Methods: Death certificates completed during a six-month period notification forms completed between January and June 2016 To investigate the accuracy of death certificate completion in Galway University Hospital, with specific emphasis on accurate documentation of common comorbidities. A retrospective review of and comparison with the deceased patients' casenotes. All death certificates were divided into those relating to patients aged over and under 75 years. Death certificates were examined for accuracy and documentation of comorbidities and these, (and the number of omissions) were compared with the actual diagnoses documented in the patients' casenotes.Results: The cause of death was accurately documented in all Death Certificates. Overall, comorbidities were more common and omissions were more frequent in the older group compared with the younger cohort, with at least one comorbidity omitted in 71% of death certificates versus 56% (p = 0.0481). For individual diagnoses, under-documentation rates were similar in both age-groups.Conclusions: While the actual cause of death was accurately completed in the death certificates reviewed in this audit, the majority of certificates in both age groups omitted one or more important comorbidity. This result may be due to an inappropriate over-emphasis in training on accurate documentation of the correct cause of death. Copyright (C) 2018, Taiwan Society of Geriatric Emergency & Critical Care Medicine. Published by Elsevier Taiwan LLC.