Abstract: Process for solid waste treatment, and particularly municipal solid waste, with recovery of the thermal energy, which is based on the general pyrolysis process modified in order to improve, on the one hand, the energy yield and, on the other, to reduce the quantity of unusable solid residues to be sent to the waste disposal, the unusable solid waste being limited to 10-15% of the total weight of the initial residue. The process and relative plant include a boosted treatment of the incoming waste, with a preliminary separation into three solid fractions, the first one of which is separately subjected to a preliminary drying step and the third one undergoes further shredding. The process and relative plant also include a section for recovering energy from the pyrolysis coke, wherein the latter is subjected to a thermochemical treatment with the production of a further quantity of synthesis gas.