The effects of chemical treatments and modifications on the tensile properties of ring- and rotor-spun cotton yarns is discussed. The rotor-spun yarns treated with zinc chloride show a higher tenacity at low stretch levels compared to sodium hydroxide, whereas with sodium hydroxide, the rotor-spun yarns show higher tenacity at higher stretch levels compared with zinc chloride. The aqueous-treated rotor-spun yarns show a higher change in tenacity compared to ring-spun yarns. Sodium hydroxide-treated yarns before resin treatment show a higher retained tenacity compared to zinc chloride-treated yarns. The substitution treatment after swelling and stretching to 100% shows a higher tenacity than that of the slack substituted yarns.