BACKGROUND: The necessity, timing and benefits of follow-up after rectal cancer surgery remain controversial, with two years traditionally considered adequate to detect most local recurrences. This unit has a policy of lifetime follow-up, and this paper investigates, at 23 years, the value of prolonged surveillance. METHOD: Six hundred and sixty consecutive patients undergoing surgery for rectal cancer were prospectively followed-up between 1978 and 2002, and local or systemic recurrence recorded. This analysis was performed on the 509/660 (76%) patients who underwent potentially curative surgery. RESULTS: Total mesorectal excision (TME) was performed in 422/509 (83%) patients, mesorectal transection in 78 (15%), and local excision in 9 (2%). Follow-up ranged from 1 to 23 years (mean = 9.7). Seven (1.4%) patients had local recurrence alone, 11 (2.2%) local plus systemic, and 86 (17%) systemic recurrence alone. Of the local recurrences 3 (17%) became evident within 1 year, 9 (50%) within 2 years, 16 (89%) within 5 years, and 2 (11%) presented after 5 years, at 5.6 and 5.8 years. Of the systemic recurrences 26 (27%) became evident within 1 year, 57 (59%) within 2 years, 93 (96%) within 5 years, and 4 (4%) presented after 5 years at 5.3, 5.3, 5.4 and 7.9 years. CONCLUSION: This long-term surveillance of patients undergoing curative surgery for rectal cancer demonstrates that most local and systemic recurrences occur within 5 years. Almost half occurred more than 2 years after surgery. However, those centres wishing to set standards of care, or evaluate current or new therapies in rectal cancer treatment, should be aware that unexpected late recurrences occasionally develop.