The role of the antral gastric vagi and the pyloric sphincter on the residual stomach following proximal gastrectomy were studied electromyographically, using adult mongrel dogs. At the first stage of surgery, proximal gastrectomy was performed preserving the bilateral antral gastric vagi followed by esophagogastrostomy by end-to-side anastomosis. The residual stomach was equipped with four bipolar silver needle electrodes and two waterproof strain gauges on the wall of the stomach. At the second and third stage of surgery, the same dog subsequently underwent trancal vagotomy and pyloromyotomy at 4 weeks intervals. Following proximal vagotomy, the interval of the BER in fasting was prolonged. Dysrhythmia was observed quite frequently, and the amplitude and rhythmicity of contractile activities of the residual stomach became lowered and distorted, however, after feeding the interval of the EBR was shortened and dysrhythmia was altered to a regular rhythmic pattern. Frequent episodes of vomiting were observed following over feeding. Subsequent trancal vagotomy showed increased incidence of dysrhythmia in fasting, and gave no favourable effects on the vomiting episodes or the amount of feeding. After pyloromyotomy, the amount of feeding could be increased by about 50% from the original optimal amount.