In this study structural or physical properties as the unevenness, hairiness and frictional properties of cotton-modal blended yarns were studied. For this purpose, 100% cotton, 50/% cotton/modal and 100% modal ring spun yarns were produced in five different twist coefficients (alpha(e) ; 3.5, 3.7, 4.0, 4.2, 4.5) and four different rem yarn linear densities (21, 25, 30 and 37 tex). General factorial design was used and the response surface was plotted for analysing the data. In conclusion, the most influential factors for the yarn characteristics were the yarn linear density and blend ratio. Contrary to expectations, the twist coefficient factor had a minor effect on yarn characteristics, especially on the friction coefficient.