A method and a structure (1) are provided for enclosing a packaging machine (100), which can be divided in at least two work areas or portions (110; 130, 120) having different operation tasks, arranged one after another along a packaging line (2) of the machine (100). The structure (1) includes a plurality of enclosing panels (P), suitably assembled together to form enclosing chambers (3, 4) for protection of each of the work portions (110; 130, 120). At least one of the enclosing chambers (3) is aimed at enclosing, a pressurized environment and at least the other chamber (4) is aimed at enclosing an environment, whose pressure is substantially constant and equal to the outside pressure.