Intra-abdominal pressure measurement is essential to the diagnosis of patients with intraabdominal hypertension or abdominal compartment syndrome. The most common method for measuring intra-abdominal pressure (IAP) is the intravesicular or "bladder" technique, which requires electronic monitoring technology not available on the typical surgical ward. Herein we describe and validate a simple, rapid screening method for bedside IAP measurement using the patient's indwelling urinary catheter and a readily available intravenous tubing extension. Validation of this technique across the clinically important IAP diagnostic spectrum demonstrated acceptable bias (1.6 mm Hg; 95% confidence interval 1.4-1.8) with limits of agreement of 0.36 to 2.8. This demonstrates good agreement between the two IAP methods and validates the bedside technique as a simple, cost-effective, and reproducible method for screening IAP measurements outside of the critical care setting.