An improved catheter infusion system is needed for esophageal intraluminal manometry. Using conventional syringe-pump infusion systems undesirably rapid infusion rates of 6 ml per min or more are often needed to achieve accurate recording of esophageal peristaltic pressure. These rapid base line infusion rates are necessitated by the high compliance of syringe-pump systems which causes substantial reduction in the infusion rate during dynamic pressure transients. In this study we tested a hydraulic-capillary infusion system designed to have low compliance. This minimally compliant system yields accurate recording of esophageal peristaltic pressure at infusion rates of 0.6 ml per min or less. We believe that the hydraulic-capillary infusion system is a useful tool for performing both clinical and investigative studies of esophageal motor function.