Abstract: This invention provides a pressure sensing catheter, and method for using the same, which eliminates the practitioners' need to fill the catheter with fluid manually prior to insertion, and thereby increases the accuracy and ease of the overall pressure-sensing procedure. The illustrative catheter includes, in its proximal end, a transducer base or housing that is permanently attached to the catheter shaft. The base includes, inserted thereinto, one or more miniaturized pressure transducer assemblies, which are in fluid communication with corresponding pressure lumens that extend down the shaft and are in communication with one or more predetermined balloons by discrete channels or ports, which provide a fluid passage between the interior space of the balloon and the corresponding pressure lumen. The integral assembly includes a predetermined, previously installed charge of fluid that extends from the transducer, through the corresponding pressure lumen and into the interior volume of the sensing balloon.