A self-consistent description of non-isothermal fracture in viscous-plastic materials is given taking into ac­count the temperature dependence of Griffith surface energy. On the basis of the crack motion equation in such materials, combined with the nonequilibrium-thermodynamical analysis of the energy dissipation near the crack tip, different regimes of crack propagation are described. It is found that thermally stimulated crack propagation leads to the acceleration of total fracture advance. Specifically, the advancement time for the quasi-adiabatic fracture condition τ(αδ) is appreciably smaller, than the analogous time for the isothermal regime τ(ιδ).