The excess molar enthalpies H-m(E) have been measured for mixtures containing methyl, or ethyl acrylates with odd n-alkanes (from pentane to heptadecane) at the temperature 298.15 K. The H-m(E) values are positive for all mixtures, increasing regularly with the alkane chain length and decreasing with the ester chain length. The behaviour of these mixtures is justified on the basis of molecular association in acrylates. The theoretical estimation of the excess enthalpies is also carried out using one group contribution model.