--- - |2+ Background Mortality studies can help reduce health inequalities by informing public policy through a better understanding of causes of death and comorbidities. Mortality studies often rely on Medical Certificates of Cause of Death (MCCD) for data. Method A systematic review was undertaken to identify the extent and nature of issues in recording causes of death for people with intellectual disability on MCCD. Results Fifteen of the 25 articles included in the literature review raised concerns about the accuracy of MCCD in identifying the cause(s) of death of people with intellectual disability. The most frequent issues were the under‐reporting of intellectual disability on MCCD, and listing intellectual disability or an associated condition as an underlying cause of death. Conclusions Concerns about the accuracy and reliability of MCCD for people with intellectual disability raise questions about mortality data based on MCCD. Clear guidance is required from WHO for those completing MCCD for people with intellectual disability. - Journal of Applied Research in Intellectual Disabilities, Volume 31, Issue 5, Page 659-668, September 2018.