Crack growth analyses of CT specimens are carried out using the three-dimensional elastic-plastic FEM. Two kinds of specimens, 1/2-inch-and 1/4-inch-thick CT specimens, are analyzed. The relation between the crack growth length and the load line displacement is measured experimentally and it is simulated by the FEM analyses. Three-dimensional fracture parameters, J integrals, are evaluated during crack growth analyses. The stress and displacement fields are obtained and compared with the HRR solutions. It is shown that the stress and displacement fields deviate from HRR solutions due to crack growth caused by the unloading effects at the near-tip regions.