In guided tissue/bone regeneration, membranes are used as barriers to prevent the faster growing soft tissue cells from entering the defect space and to regenerate periodontal ligament, cementum, and bone. The two sides of the membranes are in contact with distinct biological environments in which one faces a region in which osteointegration should be ideally promoted. Biocompatible and biodegradable composite membranes were produced by combining poly(d,l-lactic acid) and Bioglass^® particles featuring an asymmetric bioactivity and a good integration between the polymeric and inorganic fractions. The asymmetric distribution of the osteoconductive particles was produced during the processing of the membrane using a solvent casting methodology. Only the inorganic-rich face promoted the deposition of bone-like apatite after immersing the composite membrane in simulated body fluid for 2 days. The mechanical properties of the membranes were evaluated using dynamic mechanical analysis by analyzing the viscoelastic properties and the glass transition of the samples in both dry and wet states. A clear plasticization effect of water was detected, but the composite membranes were found to be stiffer, at 37ºC, compared with the pure polymer. SaOs-2 cells attached on both the surfaces and proliferated after 7 days in culture.