Esophageal motility was studied in 5 healthy adult horses, using a 4 side-hole catheter assembly continuously perfused with distilled water. Resting pressure and maximal pressures generated during swallowing were measured over the whole length of the esophagus (mean +/- S means = 132.7 +/- 2.31 cm). Four functionally distinct regions of the esophagus were demonstrated: cranial esophageal sphincter, caudal esophageal sphincter, and "fast" and "slow" regions in the body of the esophagus. The resting pressure of the cranial and caudal esophageal sphincters were 171.1 +/- 20.45 (x +/- S means) and 10.5 +/- 0.61 (x +/- S means) mm of Hg, respectively. The maximal pressure of the "fast" and the "slow" esophageal regions and caudal esophageal sphincter were 63.1 +/- 3.75 (x +/- S means), 71.9 +/- 3.65 (x +/- S means), and 63.1 +/- 2.60 (x +/- S means) mm of Hg, respectively. The length of each region and duration of pressure events were quantitated, establishing an equine esophageal pressure profile.