The standard (p ∘ =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: d-galactono-1,4-lactonel-galactono-1,4-lactoned-gulono-1,4-lactonel-gulono-1,4-lactonel-mannono-1,4-lactoneΔcUm∘(cr,298.15K)/(kJ·mol-1)−2559.09±0.47−2559.66±0.48−2561.32±0.51−2560.91±0.48−2563.43±0.37ΔcHm∘(cr,298.15K)/(kJ·mol-1)−2557.85±0.47−2558.42±0.48−2560.08±0.51−2559.67±0.75−2562.19±0.37ΔfHm∘(cr,298.15K)/(kJ·mol-1)−1232.36±0.65−1231.79±0.65−1230.13±0.65−1230.54±0.62−1228.02±0.65Δ fus H(T fus )/(kJ·mol −1 )35.77±0.3235.98±0.0640.13±0.6041.50±0.3636.13±0.20T fus /K410.32±0.03409.82±0.03459.30±0.23458.96 ± 0.05426.52±0.06The values of standard molar enthalpies of formation in solid phase of the lactones were relationed with their molecular structures and hydrogen bonding.