A process for removal of tritium from materials that are contaminated thereby envisages the use of a detritiation reactor RT, in which the reaction for the removal of tritium from the waste takes place, the waste being recovered by a flow of moist inert gas in which an extremely low percentage of humidity is used. The heated waste releases a current of tritiated gases, the current of gases being removed from the reactor via the moist inert gas, which conveys it into a membrane reactor RM for decontamination. The membrane reactor, in fact, is able to remove selectively the tritium present in the mixture of gases: there is thus the dual advantage of purifying the mixture of gases and of recovering the tritium contained therein.