This study compared simultaneous intravesical pressure readings obtained with catheter-mounted microtip transducers and external water pressure transducer catheters during filling cystometry. Women undergoing multichannel urodynamic testing were randomly assigned to one of three groups: two microtip catheters, two external water pressure transducer catheters, or one of each type. Intravesical pressure was measured simultaneously for each transducer combination in each subject for minimal and maximal Valsalva effort and minimal, moderate, and maximal cough effort at two sequential bladder volumes (150 and 300 ml). Paired t tests were used to compare the means of the intravesical pressure obtained by the two types of catheters. The largest mean differences were observed when comparing microtip and water pressure transducers. Correlations of maximum pressure were consistently high between two microtip transducers and two water pressure transducers but lower for the microtip - water combination. Excellent reproducibility was demonstrated with transducers of similar types for intravesical pressures recorded during Valsalva and cough in women without prolapse. However, considerable variability was seen in pressures recorded by different transducers, particularly dependent on the water catheter manufacturer, indicating that intravesical pressure recordings from microtip and water-based systems are not interchangeable. © International Urogynecology Journal 2005.