Fracture strength of a WC-12Co thermal sprayed coating is investigated experimentally and analytically. In the experiments, a pair of coated butt cylindrical specimens is subjected to combined tension with torsion stresses. Stress distributions in the coating at critical loading conditions are analyzed by using FEM analysis and the fracture criterion of the coating is investigated. It is found that normal stress distributions are common to all cases of testing stress conditions and so fracture condition of the brittle coating is represented as K ≧ Kcr in the normal stress distribution even under mixed deformation mode I and III. By using the experimental method presented in this paper and the corresponding FEM analysis, an approximation for the critical bonding strength of a coating under shearing load can be estimated.