This paper deals with the evaluation of the static mixed-mode stress intensity factors in case of thermal and mechanical loadings. A method and a formulation based on the J-integral and the energy release rate formulation is developed. The numerical results emphasize the effects of the temperature field on the stress intensity factors; thus, we show that an increasing temperature in the direction of the crack increases the mode 1 stress intensity factor. In addition, the formulation is also applied to the computation of an experiment consisting in a precracked glass specimen into a temperature gradient induced by a water bath and an oven.