OBJECTIVE To provide clinicians with a technology assessment of the safety and effectiveness of continuous ambulatory esophageal pH monitoring (CAEpHM) in the diagnosis of pathologic gastroesophageal reflux in adults. METHODS A literature review and a Diagnostic and Therapeutic Technology Assessment (DATTA) survey questionnaire were mailed to 118 physicians with special interest in gastroesophageal reflux, esophageal disease, or the use of CAEpHM in the diagnosis of noncardiac chest pain. These panelists had been nominated to the DATTA panel by appropriate specialty societies and medical schools. A total of 93 panelists (79%) responded. METHODS Assessment was based on the expert opinion of the panelists, as well as on published scientific and medical literature (available as of June 1, 1994). Published studies were identified by a MEDLINE search using the terms esophagitis, reflux, and gastroesophageal reflux and by review of the references cited in these primary sources. METHODS The respondents completed a DATTA survey questionnaire; the survey results were tabulated, analyzed, and interpreted by an American Medical Association medical scientist. CONCLUSIONS The safety of CAEpHM was considered to be established in adults with chronic heartburn, chronic hoarseness, persistent acid reflux refractory to therapy, laryngeal lesions, or noncardiac substernal chest pain. The safety of CAEpHM was considered to be promising in adults with episodes of apnea. The effectiveness of CAEpHM was considered to be established in adult patients with clear primary symptoms that reflect esophageal damage, such as chronic heartburn, persistent acid reflux refractory to therapy, or noncardiac substernal pain; promising in adults with chronic hoarseness; and investigational in adults with episodes of apnea.