There are two crystal planes in hydroxyapatite (Ca10(PO4)6(OH)2; HAp) that is clinically applied to artificial bone or dental root. The two crystal planes, a- and c-planes, are anisotropy. We have successfully fabricated dense HAp ceramics with preferred orientation to a-plane from single-crystal apatite fibers (AF) and apatite gels (AG). We examined the cellular response, such as adhesion, proliferation and morphology, of orthoclastic MC3T3-E1 cells, to the surface of the HAp ceramics with preferred orientation to a-plane. The initial cell attachment efficiency of the HAp ceramics with a-plane was lower than that of isotropic HAp ceramics as a control. This may be due to the difference of surface potential of the examined HAp ceramics. The proliferation of cells cultured on the HAp ceramics with a-plane was almost the same as that of isotropic HAp one.