Objective evaluation of the penile innervation in impotent patients is mostly restricted to examination of the somatic pudendal pathways. These tests provide little information on the pelvic-cavernous autonomic innervation of the corporeal bodies. Electromyography of the flaccid penile smooth muscle is a reproducible and non-invasive method of evaluating these autonomic pathways and the status of intrinsic smooth muscle. Examination techniques and normal values have been studied in 15 young and potent volunteers. Recordings in 13 patients with neuropathology and 57 impotent patients are discussed.