Contaminated defects of the abdominal wall continue to be a significant problem for patients and surgeons. The lack of sufficient tissue may require the insertion of a prosthetic material. Polypropylene (PP) mesh is still the most widely used material for this purpose, although the propensity to induce extensive visceral adhesions and erosion of the skin or intestine is a well-known drawback. Expanded polytetrafluoroethylene (PTFE) patch has better mechanical properties and has a low potential for infection. Therefore, we used expanded PTFE patch to repair contaminated abdominal wall defects in three patients. In one patient, the postoperative course was uneventful. In the other two patients, the patch had to be removed for ongoing wound sepsis and because the patch disintegrated. In an experimental study, contaminated abdominal wall defects created in Wistar rats were repaired with expanded PTFE patch (PTFE group, n = 21) or PP (PP group, n = 21). Wound infection occurred in 16 rats in the PTFE group and in 14 rats in the PP group. Two rats in each group died. Two rats in the PTFE group died as a result of peritonitis, one rat in the PP group died as a result of ileus and one as a result of peritonitis. Incisional hernia was found to be significantly more frequent in the PTFE group (n = 13) than in the PP group (n = 3). Fistula formation was only found in three rats in the PP group. Adhesion formation was more pronounced in rats in the PP group. It is concluded that the expanded PTFE is unsuitable for the reconstruction of contaminated abdominal wall defects and that PP mesh is more suitable, although this material has a high risk of complications.