This report describes the use of gastric tonometry to measure gastric mucosal ischemia/intestinal mucosa pH (pHi) in a patient treated for celiac artery compression syndrome. Significant gastric mucosal ischemia was demonstrated prior to celiac artery decompression as indicated by a pHi of 7.29. The ischemia was relieved by celiac artery decompression, with an increase in the pHi to 7.48. The patient experienced complete relief of his symptoms after surgical decompression and remains asymptomatic 14 months after surgery. Gastric tonometry provides an objective measurement of intestinal perfusion and ischemia in the treatment of celiac artery compression syndrome.