The purpose of this study was to determine whether knowledge gained (as determined by a formal course test) by surgeons in a continuing education course on total mesorectal excision and rectal cancer management is retained 1 year later. A formal course test had been previously developed and validated. The test evaluated course content including pelvic anatomy, surgical techniques, imaging, pathology, adjuvant therapies, and cancer and functional outcomes. Validation was determined by the absence of change in pre- and posttest scores of the "expert" course instructors (n = 8, P = .6) and by a linear correlation in test scores with increasing level of general-surgery resident training (n = 16, P = .001). Significant learning by the 58 surgeons taking the course had been shown by improvement in test scores from before the course (mean score 19) to after the course (mean score 25.3, P = .001, out of a possible 33 total mark). At 1 year after the course, those course participants (n = 44, 76%) who had provided postcourse contact information were asked to complete the course test again. Responses were received from 18 surgeons (41% of those surveyed, 31% of the original course participants). The mean score on the test after 1 year was 23.8. Compared with the immediate posttest scores, there was no significant knowledge loss over the year (P = .09). We conclude that knowledge acquired during a continuing education course for surgeons on total mesorectal excision and rectal-cancer management is retained 1 year later.