We hereby report a case of use of biological mesh to repair one large, contaminated abdominal wall defect due to a sigmoid tumour presented as an abscess infiltrating the abdominal wall. Our patient was a 48 years old woman. Her medical history was negative for any previous disease or surgical procedure. Because of the abscence of neoplastic secondarism an en-bloc resection of the interested sigmoid colon and of the infiltrated abdominal wall was performed, thus resulting a large wall defect in the left inguinal region. In order to close the wall defect a biological porcine collagen mesh was used. In our case we used a Permacol mesh made of porcine acellular dermal collagen. Reconstruction of complicated abdominal wall defects is a challenging surgical problem and primary repair is often difficult to achieve without excessive tension in the abdominal wall. The use of a syntethic mesh in this patient could have been inappropriate due to the possibility of creating adhesions with intra-abdominal viscera and fistula formation. We chose to use a biological mesh because of its safer properties in case of infected, inflamed or infiltrated surgical fields, as demonstrated in the literature.