Background: There are known racial and socioeconomic disparities in the use of epinephrine autoinjectors for anaphylaxis. Objective: To measure rates of epinephrine autoinjector prescription filling and identify patient demographic factors associated with filling rates among patients discharged from the pediatric emergency department Methods: This was a retrospective observational cohort study of all patients discharged from a pediatric emergency department who received an outpatient prescription for an epinephrine autoinjector between January 1, 2018 and October 31, 2019. Rates of prescription filling were calculated, and multivariable logistic regression was performed to identify sociodemographic factors associated with prescription filling. Results: Of 717 patients included in the analysis, 54.8% (95% CI 51.1,58.5) filled their prescription. There were no significant associations between EAI fill rates and patient age or sex. In bivariable analysis, Non-Hispanic white patients were more likely to fill EAI prescriptions compared to Non-Hispanic black patients (OR 1.89, 95% CI 1.11, 3.20) and patients with in-state Medicaid were significantly less likely to fill EAI prescriptions compared to those patients with private insurance (OR 0.69, 95% CI 0.48, 0.98). However, after multivariable adjustment there was no significant difference in filling by age, insurance status or race/ethnicity. Conclusions: Only approximately half the patients filled their EAI prescriptions after discharge. Filling rates do not vary by sociodemographic characteristics.