The myoelectrical activity of several sections of the digestive tract of sheep has been studied as an estimation of the gastrointestinal motility. Nickel/chromium electrodes were implanted chronically in the reticulum, rumen, omasum, antrum and duodenum. The myoelectrical signals were then recorded simultaneously and stored in a computer which calculated the integrated activity, duration and period (interval) of each separate reticuloruminal spike burst and the integrated activity (over one minute intervals) in the omasum, abomasum and duodenum. The different electromyographic parameters were standardised in sheep during a period of non-ingestion (resting period), and the physiological changes in these parameters associated with rumination and feeding were measured. The main effect induced by rumination was an increase in the myoelectrical parameters in the reticulum. Feeding enhanced the total activity in all regions studied. In the reticulorumen this increase was due to a rise in the frequency of the spike bursts, although there was a decrease in the integrated activity and duration of each individual spike burst.