Reinforced concrete piles embedded in homogeneous sandy soil were analyzed using a three-dimensional nonlinear finite element program, COM3, developed in Concrete Laboratory, The University of Tokyo. Nonlinear space frame element was used for the modeling of reinforced concrete piles. The applicability of the models was checked by comparing the analytical results with the experimental ones. It was found that the analysis was able to predict the behavior for general cases, but in the case of large deformation, the analysis underestimated the inelastic axial deformation. The difference of the analytical and experimental results was thought to be caused by the spalling of cover concrete and buckling of reinforcing bars. Hence, both cover concrete spalling and reinforcement buckling were modeled and included in COM3. Significant qualitative improvement was observed in the inelastic axial deformation al behavior of the RC piles.