Abstract: A shift mechanism for a tufting machine for controlling the transverse, lateral shifting movement of a series of needles of the tufting machine across a backing material for forming a series of cut and/or loop pile tufts of yarns in the backing in accordance with a pattern. The shift mechanism will include a motor controlled rack and pinion shift control assembly having one or more pinions, each driven by a motor, that engage and drive a rack coupled to at least one needle bar of the tufting machine, for controlling the transverse shifting movement of the needles.