Calcium phosphate (Ca-P) coating on carbon nanotubes (CNTs) was done with a biomimetic coating method. The multi-walled CNTs (MWNTs) were immersed for 2 weeks in the simulated body fluid. Observation by scanning electron microscopy showed that needle shape of Ca-P crystallites at nano-scale levels were massively grown on MWNTs. Thus the nano-architecture of crystalline Ca-P on MWNT surface could be produced by simple method and the MWNT may be acting as core for initial crystallization.