Modification of polyester fibers for more economical dyeing at lower temperatures without a carrier are considered in this study. Polyester dyeing is carried out industrially under rigorous conditions at high temperatures and under increased air pressure, and are treated with various solvents (primary alcohols) to make the fibers more permeable. As a result, the sorption properties, as well as the disperse dye dyeing ability, are improved. Dyeing of a modified polyester fabric at lower temperatures yielded better results than the standard dyeing of the unmodified polyester under the same conditions. The effects of fiber modification were analyzed through water absorption properties, wetting, swelling, differential scanning calorimetry (DSC), and Fourier transform infrared (FTIR) methods, and the degree of dyeing of the fabric was evaluated using CIELab parameters.