The true incidence of incisional hernia after wound dehiscence repair remains unclear because thorough long-term follow-up studies are not available. Medical records of all patients who had undergone wound dehiscence repair between January 1985 and January 1999 at the Erasmus University Medical Center Rotterdam were reviewed. Long-term follow-up was performed by physical examination of all patients in February 2001. One hundred sixty-eight patients underwent wound dehiscence repair. Of those, 42 patients (25%) died within 60 days after surgery. During a median follow-up of 37 months (range, 3-146 months), 55 of the remaining 126 patients developed an incisional hernia. The cumulative incidence of incisional hernia was 69 per cent at 10 years. Significant independent risk factors were aneurysm of the abdominal aorta (10-year cumulative incidence of 84%, P = 0.02) and severe dehiscence with evisceration (10-year cumulative incidence of 78%, P = 0.01). Wound dehiscence repair by interrupted sutures had no better outcome than repair by continuous sutures. Suture material did not influence incidence of incisional hernia. Incisional hernia develops in the majority of patients after wound dehiscence repair, regardless of suture material or technique. Aneurysm of the abdominal aorta and severe dehiscence with evisceration predispose to incisional hernia.