In this study, new biocompatible, nanostructured materials made of titanium alloys have been developed, manufactured and studied in terms of their biocompatibility. The major feature of such materials is to comprise structures with zero dimensionality (groups of atoms "clusters"), monodimensioned multilayers and nanophasic solid or three-dimensional nanocrystalls. Moreover, they theoretically have no limitations in chemical composition. Various samples with different compositions have been proposed, with varying parameters in their manufacturing process. A composition was found to appear more suitable for the specific demands for such applications of these materials. Moreover, cytotoxicity tests (both for direct and indirect contact) have been performed and the ability of osteogenic cells to attach, grow and differentiate on these materials has been analyzed "in vitro." The results show that even small granulometric variations of few nanometers can influence the biocompatibility of these materials in terms of their cytotoxicity and in terms of osteogenic cells attachment and growth. These data are important because they probably reflect the behavior of osteoblast cells and relate to bone remodeling "in vivo." (C) 2002 Elsevier Science B.V. All rights reserved.