Needle penetration force (NPF) is one of the main factors, which is used to determine fabric sewability. In this study, it was aimed to investigate sewability (based on NPF) of 1 x 1 rib knitted fabrics, which were produced by the separate ends of yarns. 18 types of fabrics were knitted with Ne 30/1 yarns with variations of stitch density and number of separate ends, whereas the other parameters were constant. Sewability tests were applied to fabrics after pretreatment and relaxation procedures by using the L&M sewability tester. As a result, it was seen that the number of separate ends and the stitch density have influence on the needle penetration values of 1 x 1 rib knitted fabrics.