Normally the bladder neck remains closed except during voiding. We reviewed 550 consecutive patients who underwent synchronous video/flow/pressure/electromyography studies to identify whether neurologic factors are involved in the pathogenesis of an abnormally open bladder neck. A total of 33 patients who had not undergone prior bladder neck surgery had an open bladder neck at rest. The prevalence of neurologic lesions in patients with an open bladder neck was significantly greater than in those with a normal bladder neck. However, there was no correlation between any specific lesion and the incidence of an open bladder neck. Patients with myelodysplasia had an inordinately high incidence of open bladder neck. We conclude that abnormalities of bladder neck innervation may result in a pathologically open bladder neck.