Carrier dyeing is a method of dyeing polyester materials that is used when necessary. Although usage of carriers in dyeing enables the dyeing of polyester materials at atmospheric pressure, the undesirable properties of the carriers are drawbacks. Disperse dyes are classified under different energy levels and the dyeing methods and color and fastness properties of dyed materials are associated with this classification. Carriers can be used when dyeing at higher temperatures than 100 degrees C to promote the leveling of the more difficult disperse dyes. In the presence of a carrier substance in the dye bath, the dyeing behavior of the disperse dyes may become sensitive to dyeing temperature and dye bath concentration changes. Disperse dyes may show distinct dyeing properties in combination dyeing in carrier dyeing although they belong to the same energy level. Color-matching operations made by using a color-matching software must take the sensitivity of both dye bath concentration and dyeing temperature of the disperse dyes into account in the carrier dyeing of polyester fibers. According to the experimental results obtained on individual disperse dyes in the present study, problems may arise in carrier dyeing of polyester fibers with disperse dyes in combination dyeing because of the different dyeing temperature and dye bath concentration sensitivity of dyes that have the same energy level. Combination dyeing must not be performed close to dyeing temperatures of 100 degrees C when dyeing in the presence of a carrier.