Five temporarily solubilized reactive disperse dyes were synthesized and characterized. They were applied to polyester/cotton blend fabric using one-bath dyeing method without dispersing agent. The dye that has azonaphthalene chro-mophore seemed to not only be exhausted on polyester but also react with cotton. But other dyes were selectively dyed on polyester and showed limited uptake on cotton. Good levelling as well as moderate to good colour fastness was obtained with the dyes on P/C blend fabric.