Retrospective analysis of risk-factors in 241 patients with large abdominal incisional hernia collected in a 16-year period at the Department of Surgery, University of Pavia, allows the Authors to identify the aetiological mechanism of herniation and to discuss the fundamental technical skills in wall reconstruction. The recurrence rate after primary repair was 30% (63/209 patients). In 32 patients (13.3%) plastic prosthesis was used. The side of recurrent herniation was upper midline in 12 patients (37.5%), lower midline in 6 patients (19%), right lower quadrant in 8 patients (25%), right and left flank in 4 (12.5%) and in 2 patients (6.25%) respectively. Plastic repair was performed with a polytetrafluoroethylene graft (PTFE) in 19 patients (59%), with a polypropylene mesh in 7 patients (22%); woven polyethylene mesh was used in 6 patients (19%). Recurrence after prosthetic repair was seen in 5/32 patients (15.6%) and was correlated to local sepsis in patients with poor nutritional status. The PTFE mesh was considered useful to reduce the recurrence rate of hernias and the postoperative disability. It was associated with good elasticity, adequate strength, satisfactory tissue acceptance and minimal risk of infection. However the best results need a careful preoperative evaluation, no tension on the suture line, the prevention and properly treatment of postoperative complications.