Thermodynamic description of the Ag-Dy-Sb ternary system has been performed. At first, the boundary binary Dy-Sb system has been thermodynamically assessed with CALPHAD method. The solution phases including liquid, Bcc and Hcp were described with a substitutional model, of which the excess Gibbs energies were formulated with the Redlich-Kister polynomial. All the binary intermetallic phases, i.e. Dy5Sb3, Dy4Sb3 and DySb, were treated as stoichiometric compounds. Then, combined with the thermodynamic parameters of the Ag-Dy and Ag-Sb binary systems cited from literatures, the Ag-Dy-Sb ternary system was thermodynamically assessed. The calculated phase equilibria were in good agreement with the reported experimental data. (C) 2009 Elsevier B.V. All rights reserved.