Apparatus for bundling, by strapping, PET bottles or similar containers essentially comprising a feed conveyor, a forming station, a transfer conveyor, a strapping machine and an unloading conveyor, wherein the feed conveyor is configured to feed a series of containers to the e-forming station which is configured to form ordered groups of containers comprising a predetermined number of containers with an arrangement relative to the feed conveyor, said forming station being provided at a first intermediate level, from the transfer conveyor which is configured to transfer a succession of said ordered groups of containers to the strapping station provided at a second intermediate level wherein the unloading conveyor is configured to unload said succession of ordered groups of containers and is provided at a lower level (LVINF) than said second intermediate level, characterized in that the forming station comprises stationary sequencers of the containers on a predetermined number of rows of containers parallel and oriented in the forward direction of said feed conveyor, and further comprises an end-stop wall of the containers in a front position with regard to the direction of said feed conveyor, the shape of said end-stop wall corresponding to a predetermined relative arrangement of the containers on the front face of the group of containers, the transfer conveyor being provided at a higher level than said station for forming the groups of containers, said higher level being spaced from the level of the forming station to an extent at least corresponding to the height of the containers or greater, the forming station being provided with a lifting assembly for the containers of a group formed of containers from the intermediate level of said forming station to the upper level of the transfer conveyor, the transfer conveyor being configured to unload in succession the formed groups of containers in a descent station in which the containers are transferred by means of a vertical translation, by gravity into the strapping station to the said second intermediate level the apparatus further comprising a vertically movable support for transferring from the said second intermediate level the said containers to the lower level (LVINF) of the unloading conveyor. the feed conveyor is configured to feed a series of containers to the e-forming station which is configured to form ordered groups of containers comprising a predetermined number of containers with an arrangement relative to the feed conveyor, said forming station being provided at a first intermediate level, from the transfer conveyor which is configured to transfer a succession of said ordered groups of containers to the strapping station provided at a second intermediate level wherein the unloading conveyor is configured to unload said succession of ordered groups of containers and is provided at a lower level (LVINF) than said second intermediate level, characterized in that the forming station comprises stationary sequencers of the containers on a predetermined number of rows of containers parallel and oriented in the forward direction of said feed conveyor, and further comprises an end-stop wall of the containers in a front position with regard to the direction of said feed conveyor, the shape of said end-stop wall corresponding to a predetermined relative arrangement of the containers on the front face of the group of containers, the transfer conveyor being provided at a higher level than said station for forming the groups of containers, said higher level being spaced from the level of the forming station to an extent at least corresponding to the height of the containers or greater, the forming station being provided with a lifting assembly for the containers of a group formed of containers from the intermediate level of said forming station to the upper level of the transfer conveyor, the transfer conveyor being configured to unload in succession the formed groups of containers in a descent station in which the containers are transferred by means of a vertical translation, by gravity into the strapping station to the said second intermediate level the apparatus further comprising a vertically movable support for transferring from the said second intermediate level the said containers to the lower level (LVINF) of the unloading conveyor.