A simple, non-invasive and well-tolerated technique for routine measurement of intraperitoneal hydrostatic pressure (IPP) in patients treated with peritoneal dialysis (PD) is presented. The height of the dialysis fluid in the PD line was measured, under atmospheric pressure, before drainage and during inspiration (IPPinsp) and expiration (IPPexp), taking the axillary line as the reference point of the resting subject in strict supine position. Normal values were established for a population of 18 patients treated with PD for 19.8 +/- 20.9 months under clinical and biological stable conditions. For an intraperitoneal volume of 2,820 +/- 419 ml, IPPinsp = 14 +/- 2 cmH2O; IPPexp = 12 +/- 2 cmH2O; IPP mean (defined as (IPPinsp+IPPexp)/2) = 13 +/- 2 cmH2O; IPP (defined as IPPinsp - IPPexp) = 2 +/- 2 cmH2O. IPP could not predict mechanical complications (hernia, hemorrhoids, dialysis fluid leakage) but the maximal IPPexp clinically tolerated was 20 cmH2O.