The treatment of post-operative eventration with major loss of parietal substance often justifies the use of prosthetic material. 62 post-operative patients from a series of 345 benefited from such a procedure. In the majority of cases they were patients who had undergone multiple surgery and also one or many attempts to cure the eventration (55%). The eventrations were of large volume and complex and one or more operative risk factors were present (81%). A Mersilene grid, implanted retromuscularly in all but one case, was the prosthetic material used in 96% of cases. Operative mortality in this series was zero, but unfortunately post-operative hematomas occurred in 27% of cases and one half of these became infected. Recurrent eventration (11%) was seen in all but one case where post-operative infection occurred. In five out of six cases under these circumstances this became apparent during the first post-operative year. The authors stress the fundamental importance of peri-operative care during such interventions; the quality of post-operative results depends, to a large extent, on this care and on the respect of the peroperative technical principles defined by the authors.