Voiding dysfunction is a common and debilitating consequence of multiple sclerosis (MS). The prevalence and severity of voiding dysfunction increases with the increasing severity of MS, but even the mildest forms of the disease are associated with urinary symptoms in 30% of patients. Every component of the central nervous system is involved in regulating voiding; as a result, MS can lead to a wide variety of urinary symptoms and urologic complications. The effect of MS on voiding can be classified according to the resulting function of the bladder and the urethral sphincter during storage and emptying of urine. Therapy is targeted to the specific bladder and sphincter abnormalities that occur. The primary goals of therapy are prevention of injury to the upper urinary tract (kidneys), reduction in urinary tract infections, and maintenance of urinary continence. These goals can be achieved by interventions ranging from behavioral modification to major reconstructive surgery.