PURPOSE: To obtain a color thermal transfer sheet capable of obtaining an image having excellent resolving power and having high light fastness after transfer, by coating a base material sheet with ink prepared by kneading a colorant composed of an oil-soluble dye being a complex compound, a binder and a coating control agent with org. solvent.

CONSTITUTION: A color thermal transfer sheet is prepared by coating a base material sheet with ink prepared by kneading a colorant composed of an oil- soluble dye being a complex compound having a m.p. of 60W120°C, a binder having a m.p. of 60W150°C and a coating control agent with an org. solvent. An ink layer forming by applying solvent ink is provided to the surface not opposed to a thermal head of the base material sheet and the solvent ink consists of 0.5W20pts.wt. of the colorant, 0.1,W20pts.wt. of the binder, 0.5W10pts. wt. of the coating control agent and 50W98pts.wt. of the org. solvent on the basis of 100pts.wt. of the total ink amount. When the thermal transfer sheet is set to a heat-melting type printer and heated in a state superposed on receiving paper, the oil-soluble dye being the colorant is eluted and separated from the base material sheet along with the binder by the heat of the thermal head to be transferred to the receiving paper.