Background and aims The aim of this study was to investigate sexual function and the presence of lower urinary tract symptoms (LUTS) in male patients with rectal cancer following short-term radiotherapy and laparoscopic total mesorectal excision (LTME) by physical and psychological measurements. Materials and methods Sexual function and LUTS were assessed by the use of questionnaires [International Index of Erectile Function (IIEF), International Prostate Symptom Score]. Sexual function was further assessed by the use of pharmaco duplex ultrasonography of the cavernous arterial blood flow and nocturnal penile tumescence and rigidity monitoring (NPTR). All investigations were performed prior to the start of preoperative radiotherapy and 15 months after surgery. Results Nine patients (mean age 60 years) participated. Erectile function was maintained in 71% and ejaculation function in 89%. Compared with pre-operative scores on the IIEF, a significant deterioration in intercourse satisfaction was seen following radiotherapy and LTME (7.9 vs 10.3, p = 0.042), but overall satisfaction remained unchanged (8.0 vs 7.0, p = 0.246). NPTR parameters (duration of erectile episodes, duration of tip rigidity ≥60%) decreased following radiotherapy and LTME. Patients reported a deterioration in micturition frequency (2.0 vs 1.0, p = 0.034) and quality of life due to urinary symptoms (8.0 vs 1.8, p = 0.018). Conclusion Based on these first preliminary findings, data suggest that 15 months after short-term radiotherapy and LTME in men with rectal cancer, objectively assessed sexual dysfunction was considerable, but overall sexual satisfaction had not changed. ; S. O. Breukink, M. F. van Driel, J. P. E. N. Pierie, C. Dobbins, T. Wiggers and W. J. H. J. Meijerink ; The original publication can be found at www.springerlink.com