With less than 2 % of autism research funding directed towards adults, the health-related needs of adults on the autism spectrum are relatively poorly understood. Poorer still is our understanding of the needs of those adults with comorbid autism and intellectual disability. This lack of understanding represents a significant knowledge gap, particularly given that the needs of this group are likely to be unique and nuanced. In this paper, we attempt to map the limited evidence base relating to the physical health of adults living with comorbid autism and intellectual disability and present a commentary on this obviously overlooked group. Specifically, we explore prevalence of and physical health-related needs among adults with comorbid autism and intellectual disability and the availability of evidence-based guidelines for health professionals. It is apparent that a distinct research agenda relating to comorbid autism and intellectual disability—particularly as it relates to adulthood and physical health—does not exist. Consequently, we have had to explore the separate intellectual disability and autism literatures to better understand where research gaps lie. In doing so, we hope to offer a synthesised approach to an otherwise disparate body of literature to inform future, and urgently needed, research efforts aiming to improve health and wellbeing among adults with comorbid autism and intellectual disability.