A machine (1) and a method for the treatment of hazardous medical waste; the waste is fed in a treatment chamber (4) defined inside a cylindrical containing body (3) which is mounted so as to rotate around a rotation axis (5); the waste is shred by means of a shredding device (9) which is arranged inside the treatment chamber (4); at the end of shredding the vacuum is generated and maintained inside the treatment chamber (4) for a first time interval (T1 ); at the end of the first time interval (T1 ) the vacuum generation is interrupted and vapour under pressure is fed into the treatment chamber (4) for a second time interval (T2); and at the end of the second time interval (T2) the vapour feeding is interrupted and the vacuum is generated and maintained again inside the treatment chamber (4) for a third time interval (T3).