The role of auxiliary LAB as vehicle in dyeing polyester/wool blends with disperse dyes is described. Dye exhaustion and bonding on polyester/wool samples are studied under different experimental conditions - the LAB amount, the temperature and pH value- to achieve optimum conditions. The results are compared with those obtained with and without conventional dyeing auxiliary products. Although dye exhaustion is higher in the presence of commercial carriers, the dye bonded increases markedly in the presence of auxiliary LAB in both fibers. The role played by auxiliary LAB in polyester/wool blend dyeing can provide a new method for this process.