An understanding of the relationship between gastrointestinal (GI) motility and disease is imperative for the proper treatment of large animal patients, especially as new therapeutic agents become available. However, the abundance of information that has become available in the last 2 decades makes gaining this understanding a formidable task. This article summarizes the changes in GI motility caused by some common diseases and conditions encountered in large animal practice, such as GI obstruction, postoperative ileus, resection and anastomosis, diarrhea, endotoxemia, GI parasitism, hypocalcemia, and pregnancy. J Vet Intern Med 1996;10:51–59. Copyright © 1996 by the American College of Veterinary Internal Medicine.