An investigation on the properties of solution-stretched ring spun and rotor spun cotton yams at regular time intervals was made. Significant changes in the properties of these yarns are observed. The changes in fine structure are evaluated by means of infra red spectroscopy and X-ray diffraction methods. Ring spun cotton yams exhibit better abrasion resistance than do rotor spun yarns. Abrasion resistance of NS-ring and rotor spun yams is higher than their counter parts. WS-ring spun yams are characterized by higher compression values, explaining the softness produced by the stretching treatment. The dyeability of the treated yams is also studied with reactive dye, and the color values are found to be significantly greater for WS-ring and rotor spun yams. (c) 2007 Wiley Periodicals, Inc.