In the absence of overt mucosal lesions, abnormalities of gastroduodenal motorfunction are considered to be important in the pathogenesis of many upper abdominal symptoms. These may be idiopathic, occur following gastric surgery, or in association with diseases such as diabetes mellitus. A variety of investigations have been developed to examine the motility of the stomach and duodenum. To date the most reliable and useful techniques are those which assess gastric transit either radiologically or scintigraphically. Assessment of the expulsion of radio-opaque gastric markers with a single abdominal x-ray can be performed as a simple outpatient screening procedure. More precise radioisotopic definition of delayed gastric emptying, however, requires access to a Nuclear Medicine Department. A number of other approaches are currently under investigation as potential diagnostic tests. The future role of these techniques is unclear, although 13C breath testing may soon permit rapid and simple screening of gastric emptying abnormalities without exposure to ionizing radiation. At present, other techniques such as ultrasound, antropyloroduodenal manometry, and magnetic resonance imaging have application only in research centers.