Head and neck (H&N) cancer patients undergoing radiation therapy (RT) experience toxicity and frequently require medical attention through emergency department visits (EDV) and hospital admissions (HA). Frequent hospital encounters potentially delay RT courses, negatively impact patient outcomes, and increase healthcare cost. This study aims to identify patient and treatment factors associated with risk of EDV/HA during H&N RT.This retrospective study included all patients undergoing H&N RT at a single institution from 2009 - 2019. Patients undergoing palliative RT and planned EDV/HA were excluded. All patients underwent definitive or postop RT using IMRT or VMAT. Factors evaluated for association with EDV/HA were concurrent systemic therapy, systemic therapy type, postop RT, AJCC stage, RT for recurrence, RT duration, and primary tumor site. Patient specific factors evaluated included gender, rural location, marital status, smoking status, smokeless tobacco use, and alcohol use severity. EDV/HA were included if they occurred during RT or within one month of RT completion. The primary presenting issue for EDV/HA was recorded for each patient. Analysis included the Mann-Whitney U-test and chi-squared comparisons.A total of 232 H&N cancer patients were included with 93 patients (40%) requiring EDV/HA. Overall, there were 149 EDV/HA recorded. The most common presenting complaints were dysphagia (20%), vomiting/diarrhea (18%), PEG tube issues (9%), swelling/airway issues (7%), aspiration pneumonia (7%), tracheostomy issues (5%), and facial infections (3%). Chemo-RT was administered concurrently to 158 patients (68%) with 113 (49%) receiving platinum-based chemotherapy, 34 (15%) receiving cetuximab, 3 (2%) transitioning between chemotherapy/cetuximab, and 8 (5%) receiving an unknown regimen. Patients receiving chemo-RT were much more likely to require EDV/HA (Likelihood Ratio (LR) = 35.2; P < 0.001). Postop RT was administered with or without systemic therapy to 108 patients (47%). This group was significantly less likely to require EDV/HA (LR = 15.0; P < 0.001). Patients with EDV/HA had a median RT duration of 50 days (IQR, 46 - 56), significantly longer than the median of 45 days (IQR, 42 - 50) in the remainder of the cohort (P < 0.001). AJCC stage only trended to significance and stage I-II disease still accounted for 10% of EDV/HA. Socioeconomic factors, RT for recurrence, and systemic therapy type did not significantly influence EDV/hospital encounters.Patients receiving chemo-RT for H&N cancer were significantly more likely to have EDV/HA resulting in longer overall RT courses. Other treatment factors and patient specific factors were not associated with increased EDV/HA. Proactive management of the most common presenting symptoms in this cohort could minimize hospital encounters and improve outcomes.