The motor and electrical events in the gastrointestinal tract correlate far better than do motor activity and transit of intraluminal contents. Two types of electrical phenomenon can be recorded from the smooth muscle of the bowel, namely slow waves and action potentials. Action potentials, which are superimposed on the slow waves, initiate the gastrointestinal contractions and are directly related to changes in intraluminal pressure. The characteristics of the electrical activity in the different parts of the alimentary tract are described, these being dependent on the anatomical recording site, the animal species, and the recording technique. Alterations in motility by neural and hormonal stimuli reflect the changes that these stimuli produce in the gastrointestinal myoelectrical activity.