Excess molar enthalpies, H-m(E), of binary liquid mixtures containing as component I ethylene glycol, propylene glycol, di(ethylene glycol), tri(ethylene glycol), tetra(ethylene glycol), or some PEGs, such as PEG200, PEG300, PEG400, PEG600, and 2-phenylethyl alcohol (2), have been measured over the entire range of mole fraction x(1) at 308.15 K and at atmospheric pressure, using a flow microcalorimeter. The values of HE. vary from a value of -600 J(.)mol(-1) (mixture containing PEG600) up to a maximum of 254 J(.)mol(-1) (mixture containing propylene glycol) decreasing as the chain length of glycols or PEGs increase. Curves are not symmetric, and in the case of mixtures containing PEGs, an intersection among the curves at x(1) approximate to 0.65 has been observed. Results were fitted to the Redlich-Kister polynomial to estimate the adjustable parameters and the standard deviations between experimental and calculated values. Qualitative discussion of H bonding in the liquid state is given.