Stress incontinence is more common but less difficult to control than urge incontinence. Mixed incontinence is more prevalent than urge incontinence in women while the latter is more commonly seen in men. In women, stress incontinence (SI) is generally caused by an incompetent urethral mechanism which arises from damage to the urethral sphincter or weakening of the bladder neck support that typically occurred during childbirth. Some women develop SI as a consequence of multiple anti-incontinence procedures resulting in a condition known as intrinsic urethral sphincter deficiency. In men, SI is usually a consequence of operations for benign prostatic hypertrophy or prostatic carcinoma. The mechanisms of post-prostatectomy UI may involve bladder dysfunction, sphincter incompetence, and mixed. Urge incontinence occurs when one senses the urge to void, but is unable to prevent leakage of urine before reaching the bathroom. It is usually associated with an overactivity of the detrusor muscle. Overflow incontinence is the result of the bladder's inability to empty normally. It may be due to an underactive detrusor muscle or obstruction of the urethra resulting in the overdistension of the bladder and therefore overflow of urine. Multi-channel urodynamics studies are not indicated in the first-line assessment of patients with urinary incontinence/voiding dysfunctions. Guidelines from the American Urological Association (2012), the European Association of Urology (2013) and the National Institute for Health and Care Excellence (2013) are useful in determining when multi-channel urodynamics studies should be performed.