Abstract: A patterning unit for a circular knitting machine which comprises an outer cylindrical pattern drum which is axially tricked around its periphery, the tricks being circumferentially spaced apart at the same pitch as the knitting instruments in the cylinder of a knitting machine with which the unit is to be associated, the drum being rotatable about its axis, a plurality of individually slidable selector elements arranged to function within predetermined ones only of the axial tricks in accordance with patterning requirements and, housed within the rotatable outer drum, a relatively fixed core-like inner component of cylindrical form and surrounded by a suitably contoured cam formation adapted, by co-operation with complementary formations on the selector elements, to impart to the latter sliding movements to and fro within the tricks.