Experiments leading to the development and use of a biomaterial based on reconstituted collagen for use in tympanoplasty are presented. A stable, even membrane with optimal strength and an organized matrix of collagen protein strands has been obtained. Biocompatibility was documented by subcutaneous implantation, cytotoxicity with agar overlay, cell contact, and cell-growth inhibition studies. Experimental grafting in chinchillas with perforated tympanic membranes demonstrated that the collagen membrane performed well in all cases. Histopathological studies in chinchillas showed that the collagen membrane compared favorably with fascia grafts. Of significance is that: 1. The membrane has a matrix of microperforations that enhance tissue ingrowth, allow stable anchoring, and permit aeration of the middle ear cavity. 2. The membranes obtained are not exposed to aldehyde cross-linking; therefore, tissue reaction due to aldehydes is avoided.