Aims: Abdominal leak point pressure (ALPP) measurements in female SUI may show variability because of the variations in measurement protocols. The aim of this study is to investigate the effect of cystometry catheter on ALPP measurement and compare the sensitivity of Valsalva and cough maneuvers in demonstrating urinary leakage in women complaining of SUI. Methods: In this prospective study, 194 female patients complaining of SUI underwent urodynamic studies using a 8-fr urethral cystometry and 10-fr rectal catheter. At the cystometric capacity. Valsalva and then cough ALPP was measured in semi-supine position. The same procedure was repeated after removing the cystometry catheter. The results were analyzed with Chi-square and student's t-test where appropriate. Results: In the whole study group, more patients lost urine when coughing than with Valsalva (122 vs. 93, P = 0.0013). One hundred thirty-seven (71%) women revealed a positive stress test both with and without catheter where the presence of the catheter was associated with significantly higher cough and Valsalva ALPP. In this subgroup of 137 patients, cough-induced ALPP values were significantly higher than Valsalva ALPP. Another 29 (15%) women leaked only after the removal of the catheter. Urine leakage could not be demonstrated in the rest of 28 patients (14%) with any maneuver even without catheter in the semi-supine position. Conclusion: Cough-induced stress test is significantly more sensitive than Valsalva to demonstrate urinary leakage. Cystometry catheter significantly increases cough and Valsalva ALPP whereas stress test can be false negative due obstructive effect of cystometry catheter in a group of patients. Stress test may be negative in the semi-supine position in about 14% of women complaining of SUI. Neurourol. Urodynam. 29:536-539, 2010. (C) 2010 Wiley-Liss, Inc.