Excess enthalpies for pentyl ethanoate-1-hexanol, pentyl ethanoate-n-nonane and pentyl ethanoate-1-hexanol-n-nonane mixtures at 298.15 K have been determined with a Calvet-type microcalorimeter. The UNIFAC group contribution model fitted to binary H(E) data and several modified Redlich-Kister equations have been applied to predicting ternary excess enthalpies. The predicted results agree satisfactorily with the experimental values.