We present the nurse's procedure for routine measurement of intraperitoneal hydrostatic pressure (IPP). It is very easy, simple, and safe. We measure the height of dialysis fluid in the peritoneal dialysis (PD) line before drainage. The level of the column of dialysate is measured with a scale, expressed in centimeters of water. The patient rests in a strictly horizontal position and the zero level is set at the medial axillary line. Two measurements are taken: one when breathing in and the other when breathing out. The IPP must be measured at atmospheric pressure without any counterpressure. Therefore, two techniques exist, depending on the geometry of the PD system. With disconnect systems, there is no counterpressure in the line and the empty drainage bag. With nondisconnect systems, there is always a counterpressure in the line because an air inlet is necessary. The measurement of IPP is an important element in the medical prescription of intraperitoneal volumes for adequate dialysis and to prevent mechanical complications. Normal values are established in patients undergoing CAPD treatment: IPP insp. = 14 +/- 2 cmH2O and IPP exp. = 12 +/- 2 cmH2O.