OBJECTIVE Anatomic changes induced by large hiatal hernia may alter esophageal pressure topography measurements made during high-resolution manometry. METHODS Retrospective study. METHODS Single-institution tertiary hospital. METHODS Ninety patients with large (>5 cm) hiatal hernias on endoscopy were compared with a control group of 46 patients without hernia selected from the same database of 2000 consecutive clinical high-resolution manometry studies. METHODS High-resolution manometry with at least 7 evaluable swallows for analysis. METHODS Esophageal pressure topography was analyzed for lower esophageal sphincter pressure, distal contractile integral, contraction amplitude, contractile front velocity, and distal latency time. Esophageal length was measured on esophageal pressure topography from the distal border of the upper esophageal sphincter to the proximal border of the lower esophageal sphincter. Esophageal pressure topography diagnosis was based on the Chicago Classification. RESULTS The manometry catheter was coiled in the hernia and did not traverse the diaphragm in 44 patients (49%) with large hernia. Patients with large hernias had lower average lower esophageal sphincter pressures, a lower distal contractile integral, slower contractile front velocity, and shorter distal latency time than patients without hernia. They also exhibited a shorter mean esophageal length. However, the distribution of peristaltic abnormalities was not different in patients with and without large hernia. CONCLUSIONS Patients with large hernias had an alteration of esophageal pressure topography measurements and a shortened esophagus. However, the distribution of peristaltic disorders was unaffected by the presence of hernia.