INTRODUCTION: The potential contribution of psychological and anatomical changes to sexual dysfunction in female patients following short-term preoperative radiotherapy (5 x 5 Gy) and total mesorectal excision (TME) is not clear. Aim. In this study we assessed female sexual dysfunction in patients who underwent radiotherapy and TME for rectal cancer. MAIN OUTCOME MEASURES: Genital arousal was assessed using vaginal videoplethysmography. METHODS: Sexual functioning was examined in four patients who had rectal cancer and underwent radiotherapy and TME. All investigations were done at least 15 months after treatment. The results were compared with an age-matched group of 18 healthy women. RESULTS: The patients and healthy controls showed comparable changes in vaginal vasocongestion during sexual arousal, though three out of four patients showed a lower mean spectral tension (MST) of the vaginal pulse compared with healthy controls. Subjective sexual arousal was equivalent between the two groups. CONCLUSIONS: In this study the changes of genital and subjective sexual arousal after erotic stimulus condition between patients and healthy controls were not different, though lower MST of the vaginal pulse was found in three out of four patients compared with healthy women. Additional work, however, must be performed to clarify the mechanisms of sexual dysfunction following treatment of rectal cancer.