Warp yarns, prepared as warp beam, are exposed to various forces at weaving loom. Warp yarns are bended on the back rest, subjected to friction from drop wires and healds. They are also exposed to friction and impact at reed and thereby abraded. Yarns are sized in order to increase their resistance to these effects. Sizing agents ensure that warp yarns can be weaved with sizing process. On the other hand, yarn count and yarn type (combed or carded yarn) are the significant yarn structural properties that determine and so affect the physical properties of yarn. The main reason and objective this study is to investigate the effects of yarn structural parameters (yarn count and yarn type) and sizing on the physical properties (breaking strength, elongation at break, hairiness, friction coefficient) of 100% cotton carded and combed ring yarns, sized with four different sizing agents, which were not studied in the references. It is observed that sizing process cause to decrease in the hairiness up to 99% and in friction coefficients of combed and carded yarns whereas to increase in the breaking strengths of combed and carded yarns. And also, the combed yarns had better tensile and frictional properties than carded yarns.