Background: Associations between childhood adversity and negative health outcomes are well documented within the general population; however, this relationship has yet to be confirmed in adults with intellectual and developmental disabilities (I/DD). Bridging the gap between public health and I/DD research is critical in order to better understand the ways in which the health of people with I/DD are compromised by adversity and social disadvantage and to develop preventative care frameworks and health-promoting practices specifically for adults with I/DD. The aim of this exploratory study was to examine the relationships among adversity, physical health and quality of life in a sample of adults with I/DD. Method: Participants were adults with I/DD currently residing within campus-based residences. Demographic data, psychiatric and medical diagnoses, adverse childhood experiences scores and quality of life scores were aggregated from participants' electronic medical records. A health history form was completed for each participant based on a review of participants' medical records. Results: Results indicated childhood adversity was significantly associated with number of chronic medical conditions (r = 0.35, P < 0.001, 95% BCa CI [0.13, 0.53]). Childhood adversity was not significantly related to quality of life. After controlling for demographic variables, childhood adversity remained a significant predictor of health history (B = 0.32, P < 0.005, 95% BCa CI [0.10, 0.52]), with greater adversity predicting greater medical illness. Conclusion: Participants demonstrated higher rates of childhood adversity compared with the general population, suggesting that individuals with I/DD may be particularly vulnerable to experiencing adversity during development. Childhood adversity was a significant predictor of physical illness in adults with I/DD. These findings emphasise the importance of screening for childhood adversity histories in adults with I/DD. Additionally, results demonstrate the importance of offering preventative interventions geared at preventing physical illness and promoting health in adults with I/DD with adversity and trauma backgrounds.