Introduction Febrile neutropenia is an oncologic emergency associated with significant morbidity and mortality. The objective of our study was to assess guideline adherence and clinical outcomes associated with the management of high- and low-risk febrile neutropenia patients presenting to the emergency department. Methods A retrospective observational cohort study was conducted at a 60,000-visit emergency department at an academically-affiliated tertiary referral hospital. Patients were identified as low- or high-risk using the guideline-recommended Multinational Association for Supportive Care in Cancer score. The primary outcome was the proportion of cases in which the management was concordant with applicable febrile neutropenia guidelines. Guideline adherence was defined as hospital admission and intravenous antimicrobial therapy for high-risk patients and discharge home with oral antimicrobial therapy for low-risk patients. Secondary outcomes included appropriate vancomycin administration, hospital length of stay, rates of acute kidney injury, in-hospital Clostridium difficile infection rates, and 30-day mortality. Results Of the 237 patients included, 94 (39.7%) were low-risk patients and 143 (60.3%) were high-risk patients. Guideline adherence occurred in 96.8% of high-risk patients and 0.4% of low-risk patients. Mean hospital length of stay of the low-risk group was 5 ± 5.0 days compared to 7.2 ± 7.3 days in the high-risk group. Vancomycin was often inappropriately given in 69.5% of high-risk patients. Clostridium difficile occurred in 15 (10.3%) adherent and 4 (4.4%) non-adherent patients. By 30 days, 4 (4.3%) low-risk and 15 (10.7%) high-risk patients died. Conclusion Adherence to the febrile neutropenia guidelines was low resulting in unnecessary hospital admissions of low-risk patients and frequent over-prescription of empirical vancomycin.