Ambulatory pH monitoring of the distal esophagus is the most accurate diagnostic study for patients with suspected gastroesophageal reflux disease (GERD). The measurement of proximal esophageal acid exposure time may be useful in patients with atypical reflux symptoms. The aim of this study is to evaluate if proximal esophageal pH monitoring provides useful information beyond that learned with distal esophageal pH monitoring. We routinely performed dual-channel pH monitoring with pH electrodes positioned at 20 and 5 cm above the manometric lower esophageal sphincter from January 1992 to August 1995. All patients scored their esophageal symptoms from zero (none) to four (severe). We compared proximal esophageal reflux (PR) in patients with typical symptoms (i.e., heartburn, regurgitation) and in patients with atypical symptoms (i.e., chest pain, cough, hoarseness, and asthma). We compared symptom profiles between patients with and without PR. We reviewed our experience in patients with abnormal PR, but with a normal amount of distal esophageal reflux (DR). We studied 441 consecutive patients. There were no significant differences in PR between patients with typical and atypical symptoms. There were no differences in symptom profiles between patients with normal and abnormal PR. There were no differences of PR between the different atypical symptoms. PR did not correlate with the severity of the patient's symptoms. PR correlated well only with DR. Twenty-four patients had isolated abnormal PR, but only six patients improved with antireflux therapy. We conclude that routine ambulatory esophageal pH monitoring of the proximal esophagus appears to be of little value. The decision to offer patients an empiric trial of antireflux therapy for suspected GERD should not be based on the presence or absence of PR.