Abstract: A system and method for monitoring gastric acid reflux in a patient are described. A system constructed in accordance with the present invention comprises a combination probe including a flexible tube having a pH probe disposed distally and a pressure sensor disposed a known distance proximally, the pH probe for generating pH signals in response to a hydrogen ion concentration, and the pressure sensor for generating pressure signals in response to phasic pressure changes; a display for displaying the pressure signals to aid the positioning of the probe at the LES; and a memory for storing the pH signals. A method of the present invention comprises placing the combination pH/pressure probe in the patient's stomach then withdrawing the probe until the LES respiration phasic pressure is observed from the display. Next, the probe is withdraw a known distance. This positions the pH probe at a specified distance above the LES where reflux may be monitored.