Background: Studies have shown that staff who support adults with intellectual disabilities (ID) are exposed to challenging behaviour in their work including client aggression. Exposure to aggressive behaviour has been associated with staff stress and burnout. Study samples have been small however, and there has been very little data exploring this issue among North American staff. Methods: A cross-sectional survey which included demographics, measures of frequency and severity (including perceived severity and a standardised severity score) of exposure to client aggression and the Maslach Burnout Inventory-Human Services Survey (MBI-HSS) was completed by 926 community staff who support adults with ID in Ontario, Canada. Relationships between demographic variables and exposure to aggression were examined with descriptive statistics. Pearson correlations were used to analyse exposure variables and MBI-HSS scores. Results: Nearly all staff reported being exposed to client aggression in the prior 6 months. Mean MBI-HSS scores were comparable to previously published data in similar populations with the exception of a higher score in the personal accomplishment domain. All measures of exposure to aggression were significantly positively correlated with MBI-HSS scores in the emotional exhaustion and depersonalisation dimensions of burnout. Conclusions: The prevalence of burnout in this North American sample is comparable to what has been reported in similar populations in other locations, although these staff may have a higher sense of accomplishment with regard to their work. Findings from this large sample support the evidence that exposure to client aggression affects staff emotional well-being but is by no means the only important factor. Further study is needed to explore the differences and similarities reported here as well as other contributing factors which will guide the implementation of effective strategies to improve staff well-being. (Contains 2 tables.)