Aim: To evaluate the use of transperineal ultrasonography while diagnosing stress urinary incontinence by comparing the urethral angle. Methods: A case-control study including 40 females diagnosed to have stress urinary incontinence and 40 healthy females as their controls. The proximal pubo-urethral distance, the posterior urethro-vesical angle (β-angle) and the angle of urethral inclination (α-angle) were measured at rest and during straining. Results: On analyzing the transperineal ultrasound findings, no statistical significant difference was found between cases and controls at rest, but on straining, statistical significant difference was found regarding dynamic posterior urethral angle and dynamic pubo-urethral distance (p<0.001) . Of the included 40 cases with SUI, 27 (67.5%) had cysto-urethrocele, and 5 (12.5%) had intrinsic sphincter defect (ISD). Urethral diameter was significantly different in patients with ISD (6.64±1.23 mm) when compared with patients with SUI without ISD (4.83±1.16 mm). Conclusions: Transperineal ultrasound is a simple, noninvasive, and easily conducted examination that can be used in the diagnostic workup of stress incontinence. Conclusion: Transperineal ultrasonography is a practical, reliable, non-invasive and comfortable method for evaluation of SUI. It has the advantage of dynamic evaluation during the Valsalva maneuver. Rotation angles and BND have high sensitivity and specificity for detection of SUI. The change in α angle with Valsalva (Rα) can be used as an alternative to Q-tip test.