The thermal transient in ITER, following a total LOCA accident, has been studied by means of a combined neutronic-thermal model. A complete (inboard and outboard) sector of the machine has been modelled. It turns out that, at short term, the transient is dominated by the redistribution of the high initial temperature of the plasma facing components. At medium term, the intense afterheat generation dominates the transient. The cold components act as a heat sink, and the process remains adiabatic for all practical purposes. At long term, weak afterheat generation and heat dissipation towards the environment dominate, and a temperature peak is found only several weeks after the accident. The temperatures that are obtained do not affect in any way the structural integrity or the containment of ITER.