The accuracy of esophageal manometry using the conventional perfused three-lumen catheter depends on the proper choice of the perfusion rate. Previous investigators have used a wide range of perfusion rates without considering the compliance of the transducer-catheter assembly as a variable in the selection of the perfusion rate for the hydraulic systems. We present a relationship relating the perfusion rate and the compliance which specifies the minimum adequate perfusion rate for a given transducer-catheter assembly. This approach explains apparent discrepancies in the literature regarding the proper rate of perfusion for accurate measurement of esophageal contractions. Esophageal motility tests with 10 subjects confirmed the accuracy of manometric tests at the prescribed perfusion rate (1.25 ml/min) since they compared well with intraluminal pressures measured directly with a Honeywell intraesophageal transducer. The effect of perfusion rate on the apmlitude of esophageal contraction was also investigated and it is shown that high perfusion rates result in increased amplitudes of contraction. Furthermore, at large perfusion rates a large volume of liquid builds up in the esophagus. This fluid accumulation could possibly be responsible for the increased amplitudes of contraction.