The determination of intra-abdominal pressure (IAP) may be useful in a variety of clinical situations. Despite this, invasive IAP monitoring is seldom performed due to the risks involved. Using a standard canine model of increased IAP, we evaluated the accuracy of transurethral bladder catheter pressure in reflecting IAP. Throughout the range of IAP studied (10 +/- 5 to 70 +/- 10 mm Hg), bladder pressure did not differ significantly from the direct measurement of IAP. We conclude that the measurement of bladder pressure using a standard transurethral bladder catheter provides an accurate determination of IAP.