It has been suggested that certain clinical and morphological features can modify the outcome of Crohn's disease, particularly regarding recurrence after surgery. A series of 233 patients was followed prospectively. They underwent a resectional surgical procedure for both primary and recurrent Crohn's disease during a fifteen-year period with a minimum follow-up of eighteen months. Possible risk factors for recurrence were studied. They included duration of disease before primary surgery, the type of clinical presentation at onset (whether "Perforating" or "Non-perforating"), the initial anatomical location, the presence of microscopic disease at the resection edges, the type of surgical procedure (anastomosis vs stoma), post-operative surgical complications and the age of the patient. The duration of the disease before the initial operation was the only significant factor related to the recurrence rate.