Introduction: Delirium is a common emergency department (ED) presentation in elderly patients. Urinary tract infection (UTI) investigation and treatment are often initiated in delirious patients in the absence of specific urinary symptoms, despite a paucity of evidence to support this practice. The purpose of this study is to describe the prevalence of UTI investigation, diagnosis and treatment in delirious elderly patients in the ED. Methods: We performed a retrospective chart review of elderly patients presenting to the ED at The Ottawa Hospital between January 15-July 30, 2018 with a chief complaint of confusion or similar. Exclusion criteria were pre-existing and current UTI diagnosis, Glasgow Coma Scale <13, current indwelling catheter or nephrostomy tube, transfers between hospitals, and leaving without being seen. The primary outcome was the proportion of patients for whom urine tests (urinalysis or culture) or antibiotic treatment were ordered. Secondary outcomes were associations between patient characteristics, rates of UTI investigation, and patient outcomes. Descriptive values were reported as proportions with exact binomial confidence intervals for categorical variables and means with standard deviations for continuous variables. Comparisons were conducted with Fischer's exact test for categorical variables and t-tests for continuous variables. Results: After analysis of 1039 encounters with 961 distinct patients, 499 encounters were included. Urine tests were conducted in 324 patients (64.9% [60.6-69.1]) and antibiotics were prescribed to 176 (35.2% [31.1-39.6]). Overall 57 patients (11.4% [8.8-14.5]) were diagnosed with UTI, of which only 12 (21.1% [11.4-33.9]) had any specific urinary symptom. For those patients who had no urinary symptoms or other obvious indication for antibiotics (n = 342), 199 (58.2% [52.8-63.5]) received urine tests and 62 (18.1% [14.2-22.6]) received antibiotics. Patients who received urine tests were older (82.4 ± 8.8 vs. 78.3 ± 8.4 years, p < 0.001) but did not differ in sex distribution from those than those who did not. Additionally, patients who received antibiotics were more likely to be admitted (OR = 2.6 [1.48-4.73]) and had higher mortality at 30 days (OR = 4.2 [1.35-12.91]) and 6 months (OR = 3.2 [1.33-7.84]) than those who did not. Conclusion: Delirious patient without urinary symptoms in the ED were frequently investigated and treated for UTI despite a lack of evidence regarding whether this practice is beneficial.