Weaving efficiency is greatly affected by the warp yarns strength and other properties. To improve these warp yarn properties, sizing is done with various agents either natural or synthetic sizing materials. Most of the natural sizing agents used in the industry is made of starch. Starch used is obtained from different sources with different properties. For this reason, there is the need to compare different sources of starch with and without PVA for their competitiveness. In this study two starches: potato and corn have been comparatively studied for their performance on sized yarn. Ring spun cotton yarn of 34 Nm was sized using the starches and its properties studied. The properties of the constructed fabric in terms of tensile strength, elongation, abrasion resistance and size removal percentage after desizing were also studied. End breakage rate on the loom was observed to check the weaving efficiency. From the results it was seen that the tensile strength, strength gain and abrasion resistance of yarns sized with potato starches without PVA was higher. Size removal percentage of yarns sized with potato starches with PVA was higher. Corn starch without PVA showed better result on elongation at break. Corn starch with PVA sized yarns performance was lower on overall properties and end breakage rate on loom. Yarns sized with Potato starch without PVA showed better overall performance properties and it is cost effective while corn starch showed lower performance properties and it is not cost effective