Hiatal hernias are frequently diagnosed during upper endoscopy or barium radiography. They can also be identified based on the typical 'double high pressure zone' or 'double hump' during stationary manometric pull-through. This paper aims to compare manometric and endoscopic identification of hiatal hernias. We retrospectively reviewed records of patients who had an esophageal manometry performed in our laboratory between July 2002 and July 2003. We identified 153 patients (104 females, mean age 56 years) who had both an esophageal manometry and upper endoscopy. The manometric studies were reviewed looking for the characteristic double high-pressure zone characteristic of hiatal hernia. The endoscopic reports were reviewed for the independent identification of an hiatal hernia. Information on race, gender, presence of hiatal hernias, esophagitis, and symptoms during esophagogastroduodenoscopy (EGD) exams was recorded from the reports of patients who had both EGD and manometric studies at our institution. Of the 153 patients with both endoscopy and manometry, 11 (7%) had an hiatal hernia identified by manometry compared to 51 (33%) by endoscopy. Ten (91%) of the manometrically identified hiatal hernias were also seen on endoscopy. Compared to endoscopy (gold standard), esophageal manometry had a sensitivity of 20% and a specificity of 99% for detecting hiatal hernias. Manometric identification of an hiatal hernia is an infrequent finding with low sensitivity but high specificity compared to endoscopy.