The phase diagram for the quasi-binary Tl-2 Te-Ga-2 Te-3 system was constructed based on the results of phase studies by both common thermal analysis and X-ray diffraction. Numerical values of the phase transition temperatures at different alloy compositions within the whole concentration range were listed. The diagram was compared with another diagram for the same system published earlier by other authors. The study produced substantial evidence corroborating the formation of two new chemical compounds. (C) 2011 Elsevier B.V. All rights reserved.