Introduction: Hip fractures affect over 35,000 Canadians each year. Delirium, or acute confusion, occurs in up to 62% of patients following a hip fracture. Delirium substantially increases hospital length of stay and doubles the risk of nursing home admissions and death. The primary objective of this study was to identify risk factors independently associated with acute in-hospital delirium within 72 hours of emergency department (ED) arrival for patients diagnosed with a hip fracture. Methods: This was a retrospective chart review of patients aged 65 years and older presenting to one of two academic EDs with a discharge diagnosis of hip fracture from January 1st 2014 to December 31st 2015. Multivariable logistic regression analysis was used to determine variables independently associated with the development of acute in-hospital delirium within 72 hours of ED arrival. Results: Of the 668 included patients, mean (SD) age was 84.1 (8.0) years and 501 (75%) were female. 521 (78.0%) patients received an opioid analgesic and/or femoral nerve block in the ED. The most common analgesics used in the ED were intravenous (IV) morphine (35.8%), IV hydromorphone (35.2%), or dual therapy with both IV hydromorphone and IV morphine (2.2%). Femoral nerve blocks were initiated for 36 (5.4%) patients and successfully completed in 35 (5.2%) patients in the ED. 181 (27.1%) patients developed delirium within 72 hours of ED arrival. History of neurodegenerative disease or dementia (OR: 5.7, 95% CI: 3.9, 8.4), age >75 (OR: 2.8, 95% CI: 1.4, 5.6) and absence of analgesia in the ED (OR: 2.1, 95% CI: 1.3, 3.2) were independently associated with acute in-hospital delirium. Conclusion: The development of in-hospital delirium is common in patients diagnosed with a hip fracture. We have identified modifiable and non-modifiable risk factors independently associated with acute in-hospital delirium, which can be identified in the ED. Clinicians should be aware of these risk factors in order to implement strategies directed at reducing the development of acute delirium. Additionally, further research is needed in order to understand the relationship between analgesia delivered in the ED and the development of delirium for patients diagnosed with a hip fracture.