Esophageal transit scintigraphy was introduced over 20 years ago, but its exact role in the evaluation of patients with suspected esophageal motility disorders still remains controversial. The experience with this test supplies clues, if not answers, for the following key questions: "When is it useful?", "How should it be performed?", and "Are there different methods for different applications?" Opinions vary, but it seems at the very least to be useful clinically under the following conditions: (1) when esophageal manometry is unavailable or not tolerated, (2) when manometry is equivocal or negative but a reasonable suspicion of disease remains, and (3) when clinical management will be aided by monitoring for serial change or response to therapy.