of a known water insoluble anthraquinone dye of the formula str17 12 g of sodium sulfate and as buffering agents 0 4 g of na 2 hpo 4 12h 2 o and 0 1 g of kh 2 po 4 to prepare a dye bath ten grams of mixed fabric composed of polyester and cotton 50 50 were dipped in the bath and the temperature was elevated up to 130 u00b0 c over a period of 30 minutes at which dyeing was effected for 60 minutes the fabric was taken out washed with water subjected to soaping washed with water and dried to obtain fabric evenly dyed in red the dye bath was maintained at a ph of 7 before and throughout the dyeing the degrees of exhaustion of both the disazo color according to the present invention and the known disperse dye were very satisfactory and the resulting dyed fabric showed uniformity in color and high color density light fastness of the 4th to 5th grade and chlorine fastness of the 5th minus grade test of dyeing properties of the known water soluble dyes for cellulose fibers as represented by the above described formulae a to c were conducted in.