The standard (pdegrees = 0.1 MPa) molar energies of combustion in oxygen, at T = 298.15 K, for crystalline D-,L-galactono-1,4-lactone, D-,L-gulono-1,4-lactone and L-mannono-1,4-lactone were measured by static-bomb calorimetry, by using paraffin oil as auxiliary substance and leading to the following results: [GRAPHICS] The values of standard molar enthalpies of formation in solid phase of the lactones were relationed with their molecular structures and hydrogen bonding. (C) 2004 Elsevier Ltd. All rights reserved.