Abstract: Process for incinerating refuse derived fuels to obtain fuel gas therefrom by thermal cracking, comprising the following steps: subjecting the material to deaeration; advancing a bed of material within a vacuum environment insulated from the outside (thermal cracking chamber) and in which a temperature of between 400 DEG C. and 600 DEG C. is maintained by the countercurrent flow of hot gases which lap the material; feeding the material which has passed through the thermal cracking chamber to a reactor in order to be subjected to a temperature of between 1200 DEG C. and 1800 DEG C.; in proximity ot the entry end of said thermal cracking chamber, drawing off the gases generated by the thermal cracking together with the gases which have lapped the bed of material, in order to maintain the thermal cracking chamber under vacuum; feeding the drawn-off gases to the discharge conduit for the gases generated in the reactor; purifying and filtering the gases obtained in this manner for their use as fuel gases.