We report a case of urethral diverticulum with a calculus in a 52-year-old female. She had suffered from transverse myelopathy (flaccid paralysis) as a result of multiple sclerosis. She presented with total incontinence and urinary tract infection that did not respond to antibiotic therapy. We found a urethral diverticulum calculus by X-ray imaging and urethroscopy. Transvaginal urethral diverticulectomy with removal of stone was carried out without any complications. The removed stone was 35 x 31 x 19 mm in size and was composed of magnesium ammonium phosphate and calcium phosphate.