The phase diagram for the quasi-binary Tl(2)Se-CdSe system has been established from the results of phase studies by common thermal analysis and X-ray diffraction. Numerical values for the phase transition temperatures at different alloy compositions within the concentration range 0-82 mol% CdSe were obtained. The phase diagram for the Tl(2)Se-CdSe system presented in the present paper has been compared with that published earlier by other authors, as well as with phase diagram for the analogous system Tl(2)Te-CdTe. (C) 2011 Elsevier B.V. All rights reserved.