In a laser thermal transfer printing using dye sublimation type medium, a high definition and continuous tone image can be obtained easily because a laser light is focused to small spot and heat energy can be controlled by the pulse width modulation of laser light. The ink donor sheet is composed by the laser light absorbing layer and the ink donor layer. We have investigated light-heat conversion efficiency for several IR light absorbing materials in the ink donor sheets. Carbon black, metal-phthalocyanine pigment and dye, metal complex organic compound, and cyanine dye were used as light-heat conversion materials. As experimental results of dye transfer from ink donor layer to receiving sheet by laser heating, each sample exhibits different dye transfer characteristics according to kind of light-heat conversion materials. By the measurement of absorption spectra of laser light absorbing layers after laser heating, it became clear that the phenomena such as the decomposition reaction and the crystal phase transformation of light-heat conversion materials were caused by laser heating. We have concluded that it is necessary for a high heat generation efficiency to have no change of IR light absorption by laser heating.