Introduction: This study presents demographic and clinical profiles of adults with intellectual and developmental disabilities seen at a psychiatric emergency department (ED). Predictors of admission were also identified. Methods: A retrospective chart review conducted from Oct 2016 to Jan 2017. Results: A total of 73 patients representing 105 visits were identified with suicidality or self-harm being the most frequent presentation. Information from third party sources (collateral) was recorded in the hospital chart 43% of the time. Thirty-six percent of the 105 visits resulted in hospitalization. Patients who were admitted were more likely to have collateral obtained (RR = 2.0, p <0.01), restraints used (RR = 2.5, p < 0.001), and friend/family (RR = 2.9, p < 0.01) or the police (RR = 2.3, p = 0.03) present. Conclusion: Study findings suggest that adults with intellectual and developmental disabilities commonly present to the specialized psychiatric emergency department setting. Many of these patients are inadequately supported and need stronger connections to community-based resources. Collateral information should more frequently be obtained and disability considerations could be better incorporated into management plans.