Background/Aims: Esophageal manometry is regarded as the gold standard in diagnosing the esophageal motility disorders. As manometric results are variable according to the methods and systems employed, we have had difficulty in comparing the manometric results measured by different methods and/or systems. To compare the results of esophageal manometry between infusion and non-infusion systems, we performed infusion manometry and non-infusion manometry. Methods: In 32 healthy volunteers and 108 patients with esophageal symptoms, we performed both low compliance pneumohydraulic capillary infusion manometry using 8 channel PVC catheter and non-infusion manometry using solid catheter in random order. Results: In healthy volunteers the manometric results were not significantly different between the two systems except the lower esophageal sphincter pressure, which was significantly higher in infusion system than in non-infusion system. In 108 patients complaining esophageal symptoms, the manometric diagnoses were different in 12 cases between the two systems; 5 cases were normal and nonspecific esophagea1 motility disorder, 3 cases were nonspecific esophageal motility disorder and nc>rmal, and 4 cases were hypertensive lower esophageal sphincter and normal by infusion system and non-infusion system respectively. Conclusions: In healthy volunteers the measured lower esophageal sphincter pressure was significantly higher in infusion system than in non-infusion system. In some symptomatic patients, the different diagnoses were observed between infusion and non-infusion systems, We think that we should consider a possible variation in manometric results derived from the different manometric systems employed in different studies. (Korean J Gastroenterol 1996; 28: 611 - 616)