ngineering of lower urinary tract tissue suitable for reconstructive surgery requires biomaterials as cell carriers, particularly in patients for whom autologous grafts are not available. Matrices should support growth, improve mechanical stability, feature excellent biocompatibility, and fully degrade without signs of scarring at the implantation side. A study was conducted showing a new bovine collagen type I-based biodegradable non-cross linked matrix was investigated for its suitability as a carrier for porcine and human urothelial cells in vitro. Initial cell adherence, metabolic activity, and proliferation behavior of cells isolated from tissue biopsies were analyzed. Constructs were characterized immunohistologically in comparison with matrix-free cell sheets established on plastic surface (=controls). Even for high-density seeding, adherence on collagen cell carrier (CCC) was excellent. Metabolic activity and proliferation of stratifying porcine and human urothelial cells cultured on CCC were comparable to that of controls. Immunofluorescence analysis confirmed epithelial phenotype, cell-cell junction formation and ongoing differentiation of the multilayered urothelium on CCC.