In this work, the effects of machine parameters on the fabric spirality, which is an important quality problem of single jersey knitted fabrics, are investigated. For this aim, two circular knitting machines with the same gauge, but one of them revolving in the reverse direction, are chosen. Single jersey fabric samples with the same weight per square meter and the same yarn count(Ne 20 Cotton) are knitted on the chosen machines at four different numbers of knitting systems. The effects of the number of the knitting systems and the rotation directions of the machines on the spirality angles are investigated.