This review focuses on current aspects of the novel technology of multiple intraluminal electrical impedance measurement. It presents methodological features, summarizes current results, and discusses potential implications for further research. The impedance technique assesses a bolus transport and its associated peristalsis. Validation studies showed a good analogy between physically deduced impedance characteristics and characteristics derived from cineradiography and manometry. From the impedance tracings, it is possible to distinguish between resting states, bolus transit, and wall contraction. Characteristics of a peristaltic wave can be obtained. In human studies, esophageal and small intestinal peristaltic patterns can quantitatively and qualitatively be assessed. A high resolution recording of bolus movements with interesting details of transport and mixing can be obtained. On the basis of several prior characterized impedance tracings duodenal contractile patterns have been classified, and the interdigestive and postprandial states characterized. For reflux evaluation the impedance technique was especially useful for the detection of nonacid gastroesophageal reflux, which is not detectable by pH monitoring. In summary, the main impact of the impedance technique is its capability to characterize esophageal and intestinal chyme transport. Important data on luminal chyme transport have been obtained. This technique is developing into an interesting investigative tool to complement standard techniques for study of upper GI motility, in particular for basic research.