Extending as lumbosacral plexus doses from the upper lumbar area to the lower sacrum and passing near several lower abdominal and pelvic organs, this plexus is subject to a number of injuries and diseases, most of them secondary. It can have many possible causes of lesions: trauma, tumor invasion, infection, radiatin, psoas abscess, retroperitoneal hemorrhage, iatrogenic or "idiopathic neuralgic amyotrophy".

We experienced one case of radiationinduced sacral plexopathy in 43 years old female who recieved preoperative pelvic irradiation(5,050rad, 4field technique, over 3weeks) and Mile's operation for rectal cancer and reported the case with clinical, radiologic, and electrodiagnostic findings.