The Al-Cr-Zn ternary system is assessed by the CALPHAD method. The solution phases are modelled using the Redlich-Kister formalism. The ternary intermetallic compounds are described by using the sublattice model. The main intermetallic compound tau(1), of the Al-Cr-Zn system, was treated as delta(1)-FeZn9 solid phase in accordance with its isotype structure. A comparison with experimental phase diagram is also presented.