The present study demonstrated for the first time desirable cytocompatibility properties of carbon nanofibers pertinent for bone prosthetic applications. Specifically, osteoblast (boneforming cells), fibroblast (cells contributing to callus formation and fibrous encapsulation events that result in implant loosening), chondrocyte (cartilage-forming cells), and smooth muscle cell (for comparison purposes) adhesion were determined on carbon nanofibers in the present in vitro study. Results provided evidence that nanometer dimension carbon fibers promoted select osteoblast adhesion, in contrast to the performance of conventional carbon fibers. Moreover, adhesion of other cells was not influenced by carbon fiber dimensions. To determine properties that selectively enhanced osteoblast adhesion, similar cell adhesion assays were performed on poly-lactic-co-glycolic (PLGA) casts of carbon fiber compacts previously tested. Compared to PLGA casts of conventional carbon fibers, results provided the first evidence of enhanced select osteoblast adhesion on PLGA casts of nanophase carbon fibers. The summation of these results demonstrate that due to a high degree of nanometer surface roughness, carbon fibers and PLGA with nanometer surface dimensions may be optimal materials to selectively increase osteoblast adhesion necessary for successful orthopedic implant applications.