Multiple sclerosis is an enigmatic and devastating neurologic disease. Voiding dysfunction is common and the irritative and obstructive symptoms can be disabling to the patient. Voiding symptoms alone are unreliable predictors of bladder and urethral dysfunction secondary to multiple sclerosis. This article focuses on the central role played by urodynamic studies in the initial assessment and management of the lower urinary tract. Detrusor hyperreflexia is the most common urodynamic finding. However, a variety of urodynamic patterns can be seen and voiding function may change over time with this chronic neurologic disorder.