This randomized prospective study was undertaken to compare the effectiveness of two methods used to prevent post-operative wound dehiscence in 100 high risk patients. Fifty patients were treated with a polyamide fiber mesh applied externally to the skin using a topical glue, while the other 50 patients were treated with a resorbable intraperitoneal mesh of polyglactin 910. Each patient had at least one of the following risk factors for wound dehiscence: undernutrition, malignancy, ascites, peritoneal infection, immunodepression, abdominal irradiation, repetitive surgical procedures through the same incision, or pulmonary disease. Judging criteria consisted of the development or absence of dehiscence and the frequency of abdominal wall complications. The percentage of wound dehiscence was significantly increased in patients with externally applied polyamide fiber mesh as compared to those with intraperitoneal polyglactin 910 mesh (p less than 0.01). Abdominal wall complications and the duration of healing did not vary significantly in frequency between the two groups. The intraperitoneal placement of a polyglactin mesh was more effective and better tolerated than external application of a polyamide fiber mesh.