The slow wave (SW) was studied in the dog intestine after a 15 cm long jejunal resection, by means of an automatic method which measures each individual SW cycle duration, the SW mean period and its standard deviation during 3 postoperative weeks. Distal to the site of anastomosis, the SW frequency dropped. 3 weeks after the resection, it was partially restored. The standard deviation increased as well caudad as orad to the anastomosis when compared to control dogs. The differences with the controls were even enhanced with time. These results suggest that the intestinal motility is altered at least during 3 weeks after a jejunal resection.