OBJECTIVE. Monitoring of esophageal pH is widely held to be the most sensitive test for gastroesophageal reflux, but it is expensive and is not available in all centers. Controversy surrounds the role of barium studies in the detection of reflux despite years of experience with their use. We studied the efficacy of fluoroscopic detection of spontaneous and provoked gastroesophageal reflux compared with 24-hr monitoring of esophageal pH. SUBJECTS AND METHODS. In 117 subjects with clinical findings suggestive of gastroesophageal reflux, we recorded fluoroscopic observations of spontaneous reflux and of reflux elicited by coughing, the Valsalva maneuver, rolling from supine to the right lateral position, and the water-siphon test. Subjects were considered to have reflux if 24-hr monitoring of esophageal pH within 14 days of the barium examination showed esophageal pH to be less than 4 for intervals exceeding the 95th percentile values previously reported for a control group. RESULTS. Barium studies showed unprovoked, spontaneous reflux in 26% of subjects proved by pH measurements to have gastroesophageal reflux. When the water-siphon test was used, the sensitivity of fluoroscopic detection rose to 70%, with a specificity of 74% and positive predictive value of 80%. Clinically significant reflux was detected radiographically in five patients in whom it was not detected by pH monitoring. CONCLUSION. These data are contrary to prior reports and indicate that barium studies are useful for screening patients with clinical findings suggestive of gastroesophageal reflux. The sensitivity of barium studies is highest when maneuvers are used to elicit reflux.