The standard (p degrees = 0.1 MPa) molar enthalpies of formation, at T = 298.15 K, for the liquids 2-methoxypyridine, 4-methoxypyridine and 2,6-dimethoxypyridine were determined by static bomb combustion calorimetry. The standard molar enthalpies of vaporization, at T = 298.15 K, were measured by Calvet microcalorimetry. The standard (p degrees = 0.1 MPa) molar enthalpies of formation of the three compounds studied, in the gaseous phase, at T = 298.15 K have been derived from the corresponding standard molar enthalpies of formation in the liquid phase and the standard molar enthalpies of vaporization, yielding ((-42.7 +/- 1.9), (-18.2 +/- 1.8) and (-233.5 +/- 1.8)) kJ . mol(-1), for 2-methoxypyridine, 4-methoxypyridine and 2,6-dimethoxypyridine, respectively. (C) 2011 Elsevier Ltd. All rights reserved.