Purpose: Various materials have been used to make guided bone regeneration membranes. The purpose of this study was to create a novel osteogenic membrane without synthetic material. The osteogenic potential of the membrane was evaluated by both in vitro and in vivo testing. Materials and Methods: The membrane was obtained by continuous culture of marrow stromal cells. The structure of the membrane was characterized by staining with hematoxylin-eosin, von Kossa, and carboxyfluorescein diacetate; immunohistochemical staining against collagen type I; electron microscopy; and energy-dispersive spectrometry. The osteogenic potential and bone augmentation effect of the membrane were investigated by implantation of the membrane and a membrane/natural coral composite into nude mice, respectively. Results: The membrane was composed of living cells and a dense matrix of collagen type I. Mineral deposition was apparent through electronic microscopic observation and von Kossa staining. Energy-dispersive spectrometry indicated that the calcium:phosphorus ratio of mineral was 1.71 in the membrane. The membrane had formed a thin layer of bone 2 months after implantation subcutaneously. In the bone augmentation specimens, new bone was observed histologically on the surface and in the pores of natural coral in all specimens of membrane-coral composite. Conclusions: This study developed a novel strategy to produce a vital guided bone regeneration membrane without synthetic material. Membrane derived from marrow stromal cells was osteogenic and had an optimizing bone augmentation effect. Schlagwörter: bone marrow stromal cell, coral, guided bone regeneration, membrane