The problem of determining the steady-state temperature and flux fields in a material containing a plane crack along the bonded interface of two dissimilar functionally graded isotropic materials is considered. The materials exhibit quadratic variation in the coefficients of heat conduction. At large distances from the crack, a uniform heat flux is prescribed. The crack is modeled as an insulated cut. Numerical values for the temperature and flux are obtained for some particular materials. The results demonstrate how the variation in the functional gradation of the thermal parameters in the bonded materials affects the temperature discontinuity across the crack faces and the heat flux flow around the crack tips.