For many years perineal neurogenic abnormalities in stress urinary incontinence have been described using electromyography examination, evoked potentials or neuromuscular biopsy. Swash suggested that progressive denervation of the stretched pelvic sphincter musculature that occurs in genuine stress incontinence is due to repeated stretch injury of the innervation of these muscles when the pelvic floor diaphragm is weak. New investigations such as perineal nerve motor latency confirmed this hypothesis. A real "perineal stretch neuropathy" can be described. It is probably very important to know about this neurogenic factor before considering surgery or rehabilitation therapy and in cases of recurrent stress incontinence. 40 cases are described.