Thirteen mongrel dogs equipped with four bipolar electrodes and three strain gauges on the anterior wall of the stomach underwent three types of vagotomy: truncal vagotomy (TV)-6 dogs; selective proximal vagotomy (SPV)-3 dogs; and antral vagotomy (AV)-4 dogs. Electrical and contractile activities of the stomach were examined before and after these vagotomies on both the fasting and postprandial states. TV caused an increased incidence of dysrhythmia and a 12 to 33% reduction of the propagation velocity of the basic electrical rhythm (BER). Following feeding, the characteristic waxing and waning pattern of normal gastric contraction was altered to a monotonic steady pattern, increasing overall contraction activity of the pyloric sphincter. These changes seem to be attributable to delayed gastric emptying following truncal vagotomy. SPV reduced the propagation velocity of the BER slightly (2.5-7.3%), preserving the inherent physiological contractile activity in the antrum and pyloric sphincter, and transforming the contractile activity in the corpus to a more monotonic pattern. AV effected a localized monotonic contractile activity in the antral region with no changes discernible in the body and pyloric sphincter. The propagation velocity was not changed significantly by antral vagotomy. The discharge interval of the BER was not altered significantly by these vagotomies.