Accurate radiological visualisation of the urethra, urethrovesical junction and bladder base is assuming increasing importance in the study of mechanical disturbances of these structures in women suffering from stress incontinence of urine. It is also valuable as a means of controlling the operative or non-operative treatment of this trouble-some complaint, and it offers a means, hitherto neglected, of research into the anatomy and physiology of the female bladder and urethra.Adequate study of the female urinary apparatus demands radiography in at least two planes and with the organs in different functional states. Significant departures from the normal may become apparent only when the patient is straining or voiding urine. The technical problems involved have hindered many workers in the past, but they can be overcome, and the object of this communication is to describe methods which have been used regularly for two years and which make it possible for cystourethrography to be carried out as a routine procedure in any X-ray department.Cystourethrography has been used in the male for more than forty years, but the first attempt to apply it to women appears to be that of Norris and Kimbrough (1928), who studied both normal and incontinent women by means of antero-posterior skiagraphs. The advantages offered by lateral views were appreciated by Thomsen (1930, 1932), but the difficulties involved forced him to resort to 45 deg. oblique exposures of the pelvic organs.