A method and machine for on-line treating and/or processing containers (2), whereby a container (2) is fed along a production line (45), a portion of which is defined by an endless conveyor (3) extending through a loading station (43; 55) and an unloading station (41; 55) for containers (2); the container (2), as it is fed along by the conveyor (3), being subjected to a treatment and/or processing operation inside a respective cell (17), which is movable with the conveyor (3) to receive the container (2) at the loading station (43; 55) and to release the container (2) at the unloading station (41; 55).