A unit for grouping packages along a transfer path includes an input station receiving the packages arranged in longitudinal lines parallel to the transfer path; an output station for groups defined by a given number of packages from respective longitudinal lines and aligned in at least one line crosswise to the transfer path. A movable conveying surface is supplied at predetermined time intervals with a number of packages equal to that in each group, and which feeds the packages along the transfer path. At least one aligning member is moved cyclically along a first path having a work portion parallel to the transfer path, and at least one push member is moved cyclically along a second path having a work portion parallel to the transfer path. The aligning member and the push member are moved respectively by independent first and second conveying mechanisms, and the work portions of the first and second paths coincide with each other.