Abstract: A control unit for a sewing machine includes a mechanism for mechanically positioning the stitch-forming members and a pattern memory unit for controlling this mechanism, from which stitch position detemining code words belonging to a specific pattern can be selected by the operator. The code word for determining a stitch position is read from the pattern memory into a shift register. The shift register is shifted in relation to the movement of the main shaft of the sewing machine so that code words for each successive stitch of a pattern are successively made available to the mechanical positioning mechanism. The succession of code words in a pattern can be recirculated in the shift register at the end of a pattern cycle, for repetition of the pattern.