A radioisotope scintiscanning technique that can document pulmonary aspiration of gastric contents in patients with gastroesophageal reflux is described. Six patients with suspected nocturnal aspiration from reflux were studied. Three of the six had positive lung scans 8 hr after intragastric placement of 10 mCi of technetium 99m sulfur colloid. Overnight intraesophageal pH monitoring revealed prolonged episodes of GE reflux in those with positive scans. These preliminary observations suggest that this scintigraphic technique may be an effective method for documenting pulmonary symptoms as a consequence of gastroesophageal reflux.