Background: This paper reviews what is currently known about mortality among Canadians with intellectual and developmental disabilities and describes opportunities for ongoing monitoring. Methods: In-hospital mortality among adults with intellectual and developmental disabilities in Ontario was examined using hospital data. Mortality was compared between age-, sex- and residence area-matched groups of Manitobans with and without intellectual and developmental disabilities using linked administrative data. A retrospective cohort study of mortality among individuals with intellectual and developmental disabilities in a region of Ontario focused on measuring excess mortality and risk factors. Findings: There is evidence of excess mortality in persons with intellectual and developmental disabilities in Canada. Some of the excess is attributable to comorbidities that are more common in this population. Women may have a greater risk of death than men. Excess mortality occurs at all ages but is more pronounced in early life. Discussion: High-quality ongoing monitoring of mortality among individuals with intellectual and developmental disabilities is possible in Canada. Examination of sex differences should be a priority.