The purpose of this study was to provide experimental evidence for the role of Gore-Tex polytetraflourethylene as an abdominal wall prosthesis. This was achieved by evaluating tissue reaction in animals to the plastic and comparing it to that of Marlex mesh. Ten Wistar rats received especially prepared Gore-Tex implants, and another ten received Marlex. The materials were inserted in a fashion that yielded results both intraperitoneally and extraperitoneally. Gross and microscopic data were recorded at the time of sacrifice, which ranged from two to ten weeks postoperatively. Grossly, both plastics were found to be similar in intraperitoneal tissue reaction. Microscopically, all of the Gore-Tex grafts retained their original shape and demonstrated focal adherence to the muscle. In contrast, strands of Marlex showed disorganization in the host in 90 per cent of the specimens and no focal adherence to muscle. Instead, it was seen walled off in fibrous tissues. It was concluded that specifically formulated Gore-Tex may provide the more suitable abdominal wall prosthesis and that further research is necessary.