Endoscopic ultrasonography (EUS), performed by means of an endoscope equipped with an ultrasound transducer, has been used in the imaging, staging, and follow-up of esophageal cancer for a decade. Although at first considered as a more or less experimental procedure, it emerged in the last six years as a valuable and precise tool for the assessment of various upper GI disorders. It is now well established that EUS can provide more accurate staging information on upper GI pathology than other imaging techniques such as conventional radiology, conventional ultrasound, CT, MRI and endoscopy. However, it remains complementary to other imaging methods, and is not suited for routine screening purposes. The instrumentation, technique, limitations, pitfalls, accuracy, and possible future of EUS are discussed, particularly concerning esophageal cancer.