The esophagus is subject to a variety of disorders that can be mechanical or functional in origin. In addition, GERD is quite common and can present with atypical manifestations. Mirroring these disorders, the esophageal function tests can likewise be broken down into anatomic and functional studies. The barium esophagogram, when properly performed, is probably the single most important test because it evaluates both oropharyngeal and esophageal anatomy and motility as well as the presence or absence of GERD. Endoscopy allows direct inspection and sampling of the esophagus. Esophageal scintigraphy and manometry play less important but well defined roles. Finally, the advent of prolonged ambulatory esophageal pH monitoring has advanced our knowledge about GERD and has particularly helped in the diagnosis of patients with atypical reflux presentations such as chest pain and pulmonary or otolaryngologic symptoms.