The effect of carrier concentration and dye type on carrier and dye uptake of Dacron type 54 yarn was determined. Disperse Red 60 and Disperse Yellow 54 dyes were used. 0-phenyl phenol was used with six different concentrations of this carrier (0, 1, 2, 3, 4 and 5 gm/l). Spun Dacron type 54 polyester yarn of 490 denier weighing ten grams was obtained. Dyeing was done using the Ahiba Texomat dyeing machine. The standard composite curves and equations were established for both dyes as well as the carrier. The dye in the yarn was extracted with dimethyl formamide as a solvent using the Fisher Shaking Water Bath. To measure the dye and carrier uptake of the polyester yarn, the extraction and dye bath solutions were analyzed spectrophotometrically. A two-way factorial Analysis of Variance (ANOVA) was used to test the hypotheses. The first null hypothesis indicating that there will be no difference in the uptake of disperse dye by polyester fiber due to initial carrier concentration was rejected. The second null hypothesis indicating that there will be no difference in the uptake of disperse dye by the polyester fiber due to dye type was also rejected. The third and fourth null hypotheses of no difference in the carrier uptake of polyester fiber due to initial carrier concentration and dye type respectively were likewise rejected. The results of this study indicated that both carrier concentration and dye type as well as their interaction have a significant effect on dye and carrier uptake of the polyester yarn. / Master of Science