© 2021, Kuwait Medical Association. All rights reserved.Objective: To evaluate the diagnostic accuracy of bladder wall thickness (BWT) and detrusor wall thickness (DWT) measurements by transvaginal ultrasound in diagnosis and classification of urinary incontinence Design: Fifty-one women with pure stress urinary incontinence (SUI), 53 women with pure detrusor over activity incontinence (DOI), both of which were diagnosed by urodynamic studies, and 50 women without urinary incontinence (as controls) were enrolled in this prospective cross-sectional study. Settings: Using transvaginal probe, BWT was measured in three sites: at the thickest part of the dome of the bladder, the trigone and the anterior wall of the bladder. Measurements are taken first at 250-300 ml bladder volume and repeated after voiding at <50 ml bladder volume. Subjects: An average of the three measurements was considered as the mean BWT and DWT. Intervention: BWT and DWT at both empty and full bladder were significantly thicker in DOI group than in controls. DOI group measurements were also thicker than SUI group, except for DWT measurement in full bladder. Main outcome measure: There were no statistical differences in DWT and BWT measurements between SUI and control groups. Results: By using ROC curve analysis, the best cut off values for predicting the DOI were calculated as 4.35 mm for full BWT; 1.95 mm for full DWT; 5.95 mm for empty BWT and 2.25 mm for empty DWT. Conclusion: Transvaginal ultrasonographic measurement of BWT and DWT in full and empty bladder can be valuable in diagnosis of DOI with low sensitivity and relatively high specificity.