Liquid liquid equilibria for the systems water + benzonitrile + N-methylacetamide and water + benzonitrile + N,N-dimethylacetamide were measured in the temperature range of (288 15 to 328 15) K at atmospheric pressure Phase diagrams. including binodal curves mid tie lines, are reported for both systems at each temperature The plait point compositions have been calculated by Hand's method Enthalpy changes for the transfer of the substituted acetamide from benzonitrile to water are given.