A container labeling machine, comprising a base structure which forms a region for the input of the containers to be labeled and at least one region for the output of the labeled containers and supports means for the conveyance of the containers (4, 6) from said input region to said output region, there being, along said conveyance means, at least one container labeling assembly, characterized in that said conveyance means comprise at least one first carousel and at least one second carousel, each provided with respective supporting plates for individual containers, at least one respective labeling assembly (10a, 10b) being associated with each one of said first and second carousels (8a, 8b), said conveyance means comprising, substantially at said input region, means for sorting the containers fed to said input region toward one and the other of said carousels (8a, 8b), and comprising means for unloading the labeled containers from said carousels (8a, 8b) and for sending the labeled containers toward said output region; said sorting means comprising at least one first selection star conveyor, which is adapted to receive the containers to be labeled fed to said input region, said at least one selection star conveyor being provided with means for the removable retention of the containers which can be activated or deactivated on command in order to allow the sending of the received containers from said at least one selection star conveyor selectively toward one or the other of said carousels (8a, 8b); wherein said at least one first selection star conveyor is adapted to send the containers to be labeled, received one after the other in input, alternately toward said first carousel and toward said second carousel wherein said unloading means comprise, downstream of said carousels (8a, 8b), along the advancement direction of the containers from said input region to said output region, at least one output star conveyor that is adapted to receive the labeled containers that arrive from said carousels (8a, 8b) and to send them toward said output region wherein said at least one first selection star conveyor is connected directly to said first carousel and is connected to at least one first transfer star conveyor which is adapted to receive from said first selection star conveyor the containers to be labeled which are intended for said second carousel wherein it comprises a second selection star conveyor, which is adapted to receive in input the labeled containers in output from said first carousel and the containers to be labeled in output from said at least one first transfer star conveyor, said second selection star conveyor being adapted to send the labeled containers received from said first carousel toward said output region and to deliver the containers to be labeled received from said at least one first transfer star conveyor directly to said second carousel. said sorting means comprising at least one first selection star conveyor, which is adapted to receive the containers to be labeled fed to said input region, said at least one selection star conveyor being provided with means for the removable retention of the containers which can be activated or deactivated on command in order to allow the sending of the received containers from said at least one selection star conveyor selectively toward one or the other of said carousels (8a, 8b); wherein said at least one first selection star conveyor is adapted to send the containers to be labeled, received one after the other in input, alternately toward said first carousel and toward said second carousel wherein said unloading means comprise, downstream of said carousels (8a, 8b), along the advancement direction of the containers from said input region to said output region, at least one output star conveyor that is adapted to receive the labeled containers that arrive from said carousels (8a, 8b) and to send them toward said output region wherein said at least one first selection star conveyor is connected directly to said first carousel and is connected to at least one first transfer star conveyor which is adapted to receive from said first selection star conveyor the containers to be labeled which are intended for said second carousel wherein it comprises a second selection star conveyor, which is adapted to receive in input the labeled containers in output from said first carousel and the containers to be labeled in output from said at least one first transfer star conveyor, said second selection star conveyor being adapted to send the labeled containers received from said first carousel toward said output region and to deliver the containers to be labeled received from said at least one first transfer star conveyor directly to said second carousel.