Postoperative electromechanical activity of the gastric antrum, small bowel, right colon, and sigmoid colon was recorded in stumptail monkeys in response to retroperitoneal dissection and transient clamping of the renal pedicle. Bipolar silver electrodes and extraluminal bonded strain gauge transducers were used to record slow-wave and spike discharges and contractions of intestinal smooth muscle. After operation myoelectric activity was decreased transiently in the antrum and for only a few hours in the small bowel. Right colon contractile activity was decreased significantly for 24 hours and that of the sigmoid colon for 72 hours. Postoperative inhibition of bowel motility appears to be most profound and persistent in the colon.