Urinary and sexual dysfunction are recognized complications of rectal cancer surgery in men. This study compared robot-assisted total mesorectal excision (RTME) and laparoscopic total mesorectal excision (LTME) with regard to these functional outcomes. A series of 32 men who underwent RTME between February 1, 2009 and December 31, 2010 were matched 1:1 with patients who underwent LTME. The matching criteria were age, body mass index, tumor distance from the anal verge, neoadjuvant chemoradiation therapy, and tumor stage. Urinary and erectile function were evaluated using the International Prostatic Symptom Score (IPSS) and the five-item version of the International Index of Erectile Function (IIEF-5) scale. Data were collected from the two groups at baseline and at 3, 6, and 12 months after surgery and compared. The mean IPSS score did not differ between the two groups at baseline at any point of measurement. The mean baseline IIEF-5 score was similar between the two groups and was decreased at 3 months. The mean IIEF-5 score was significantly higher in the RTME group at 6 months than in the LTME group (14.1 ± 6.1 vs. 9.4 ± 6.6; p = 0.024). The interval decrease in IIEF-5 scores was significantly higher in the LTME group than in the RTME group at 6 months (4.9 ± 4.5 vs. 9.2 ± 4.7; p = 0.030). The men in the RTME group experienced earlier restoration of erectile function than did those in the LTME group. Bladder function was similar during the 12 months after RTME or LTME.