The impact of hiatal hernia (HH) on oncologic outcomes of patients with esophageal adenocarcinoma (AC) remains unclear. The aim of this study was to assess the effect of pre-existing HH (≥3 cm) on histologic response after neoadjuvant treatment (NAT), overall (OS) and disease-free survival (DFS). All consecutive patients with oncological esophagectomy for AC from 2012 to 2018 in our center were eligible for assessment. Categorical variables were compared with the X 2 or Fisher's test, continuous ones with the Mann-Whitney-U test, and survival with the Kaplan-Meier and log-rank test. Overall, 101 patients were included; 33 (32.7%) had a pre-existing HH. There were no baseline differences between HH and non-HH patients. NAT was used in 81.8% HH and 80.9% non-HH patients (p = 0.910), most often chemoradiation (63.6% and 57.4% respectively, p = 0.423). Good response to NAT (TRG 1-2) was observed in 36.4% of HH versus 32.4% of non-HH patients (p = 0.297), whereas R0 resection was achieved in 90.9% versus 94.1% respectively (p = 0.551). Three-year OS was comparable for the two groups (52.4% in HH, 56.5% in non-HH patients, p = 0.765), as was 3-year DFS (32.7% for HH versus 45.6% for non-HH patients, p = 0.283). HH ≥ 3 cm are common in patients with esophageal AC, concerning 32.7% of all patients in this series. However, its presence was neither associated with more advanced disease upon diagnosis, worse response to NAT, nor overall and disease-free survival. Therefore, such HH should not be considered as risk factor that negatively affects oncological outcome after multimodal treatment of esophageal AC.