Excess molar enthalpies, H-m(E), of binary mixtures containing poly(ethylene glycol) (PEG) 200 + 1,3-dioxolane, PEG 200 + 1,4-dioxane, PEG 200 + oxolane and PEG 200 + oxane were determined using a flow microcalorimeter at (288.15, 298.15 and 313.15) K and at atmospheric pressure. The H-m(E) curves are always positive, with maxima varying from 393J mol(-1) (1.3-dioxolane) to 658 J mol(-1) (oxolane), showing asymmetrical trends. The effect of the temperature is well marked on the calorimetric data that increase as the temperature is increased. The Redlich-Kister polynomial was used to estimate the binary fitting parameters. Root-mean-square deviations from the regression lines are reported.