The surgical management of large body wall defects presents special challenges. The prosthetic materials employed for these defects, although readily available, have the disadvantage of susceptibility to infection. Autologous tissue is frequently not available in sufficient quantity. The long-term functional and histologic results of the use of preserved human dura for closure of abdominal wall and diaphragmatic defects have been evaluated. Dural patches were sutured into abdominal wall and diaphragmatic defects of six dogs, using interrupted sutures of Dexon and Prolene. The animals were killed eight, 16 and 24 weeks after patch placement. The strength of the material was tested with a pneumoperitoneum prior to death and in all animals it appeared firmly incorporated into the host tissue. Histologically there was a mononuclear inflammatory response seen at eight weeks, with resolution by 24 weeks. Ingrowth of surrounding collagen and muscular tissue produced a firm union between the homologous material and the host tissue. The results of this study indicate that preserved human dura is an excellent material for closure of body wall defects. It appears to be well tolerated by host tissue and maintains its strength over prolonged periods of time.