Following tooth extraction, bone resorption and remodeling are inevitable; therefore, guided bone regeneration (GBR) is essential in current implantology. In this procedure, collagen membranes act as biological barriers that prevent epithelial ingrowth and promote osteogenesis. The objective of this study was to compare in vitro the tensile strength and degradation of the Geistlich Bio-Gide and Tissum Sus-Mem collagen membranes. The research methodology was experimental, comparative, preclinical, and in vitro. The study population and sample comprised 68 specimens, which were distributed among analyses of surface morphology, mechanical properties, hydrophilicity, and degradation. Chemical composition and morphology were analyzed by means of scanning electron microscopy and EDS analysis; hydrophilicity was determined through contact-angle measurements; mechanical properties were examined by uniaxial tensile tests under wet and dry conditions; and, finally, degradation was investigated in a collagen solution and in artificial saliva over 7, 14, and 21 days. The findings revealed functional and structural differences between the two membranes. Bio-Gide showed much higher hydrophilicity (p < 0.001) and had a well-defined bilayer morphology. Sus-Mem showed, in addition to a much higher tensile strength (p < 0.001), a dense fibrillar structure.