Marlex and Gore-tex, two prosthetic materials used to close abdominal wounds, were compared with respect to strength and adhesion formation. A 2.5 X 3.5-cm full-thickness area of abdominal wall was excised in 32 CD rats. The defect was repaired using identically sized patches of Marlex or 1-mm Gore-tex, determined by alternate assignment, and sutured with continuous 4-0 Gore-tex. Adhesion formation was graded at necropsy and recorded photographically in each animal. The mean adhesion index (none = 0, maximal = 4) was 1.37 +/- 0.12 and 2.62 +/- 0.12 (mean +/- SEM) for Gore-tex and Marlex groups respectively (p less than 0.005, unpaired t-test). A template was used to fashion 2-cm coronal strips of abdominal wall for tensile-strength testing. The relative strengths were 2.67 +/- 0.14 and 3.02 +/- 0.16 kg/cm (mean +/- SEM) for the Gore-tex and Marlex groups respectively (NS). Histologically, there were more epithelioid giant cells and less collagen formation in the Gore-tex group. Abdominal wall reconstruction with Gore-tex resulted in wound strength equal to that of Marlex and fewer adhesions. Gore-tex is preferred when prosthetic material and viscera are in close proximity.