Background: Epiglottic entrapment (EE) is a common cause of poor performance in racing standardbreds (STBs) and thoroughbreds (TBs). There is limited information published on the condition in STB racehorses or factors associated with return to racing for both breeds. Objectives: 1) Describe the clinical presentation, post-surgical complications and prognosis for TB and STB horses following EE surgery, 2) Describe post-surgical racing performance of TB and STB horses following EE surgery and 3) Compare racing performance between horses undergoing EE surgery and their maternal siblings. Study Design: Retrospective cohort study. Methods: Veterinary clinical records and racing data were used to compare pre-surgical findings, post-surgical complications and racing performance in STBs and TBs undergoing surgical correction of EE. Associations between signalment, pre-surgical findings, complications and racing post-surgery were compared using logistic regression analyses. Racing performance following surgery was compared to maternal siblings using conditional logistic regression. Results: There were 82 cases where EE surgery was performed at least once: 33 STBs and 49 TBs. In total, 74% of cases raced following surgery. Cases with severe inflammation post-surgery (P<0.001), airway complications (P<0.001) or re-entrapment (P<0.01) were at a lower odds of racing post-surgery. TB cases were 5.5 times (95% Confidence interval 1.61 to 18.73) more likely to race than their maternal siblings (P<0.01). Main Limitations: Retrospective design from a single hospital population. Matched siblings were used as controls, and it was assumed they did not suffer from EE or another performance inhibiting condition. Conclusion: Horses with thicker, more inflamed, ulcerated entrapping membranes are more likely to suffer from post operative inflammation and concurrent airway pathology. In the current study, TBs with EE are more likely to race compared to their maternal siblings.