In the present paper, nanocrystalline diamond films (NDFs) were fabricated on optical glass using microwave plasma assisted chemical vapor deposition (MPACVD). The suitable processing parameters are as followings: methane concentration 3% in argon, total deposition pressure 13.3 kPa, substrate temperature 500 °C. The diamond films were characterized by means of scanning electron microscopy (SEM), X-ray diffraction (XRD) and Raman spectroscopy. In vitro osteoblast cell cultures and platelet adhesion tests were applied to evaluate the biocompatibility of the nanocrystalline diamond films (NDFs). All results indicate that the diamond films exhibit better tissue compatibility and hemocompatibility which are very suitable for biomedical applications.