Background: Measurements of maximum urethral closure pressure (MUCP) are a part of urodynamic investigations preceding an incontinence surgery and a part of urethral function tests. Objectives: The aim of the study was to compare maximum urethral closure pressure determined by a microtip catheter with those measured by an air-charged catheter. Material and methods: A prospective randomized study in a tertiary referral centre. 122 female patients with urodynamic stress incontinence were randomly assigned to have their urethral pressure profi les measured at rest by both microtip and air-charged catheters. Intervention and Measurements: Each patient had three measurements taken by each catheter type. Means of the measurements were compared with regard to correlation and repeatability. For statistical analysis, an approach proposed by Bland-Altman was applied to assess the agreement between the two techniques. Results: Correlation coeffi cient between MUCP by the air-charged and the microtip catheter was r=0.8507(95% CI 0.7928 – 0.8934; p<0.0001). MUCP by the air-charged catheter was signifi cantly lower than MUCP measured by the microtip catheter. The two-tailed p value was <0.0001, considered extremely signifi cant. (95% CI of the diff erences; mean diff erence = -3.033; mean of paired diff erences -3.730 to -2.335). Discrepancies between measurements of the microtip and the air-charged catheters suggest good agreement between the two catheters since the mean diff erence was 2.8 cmH2O and the 95% CI of agreement were narrow with -0.03319 to 0.3151. Conclusion: Air-charged catheters give lower readings for