The standard (p ∘ =0.1MPa) molar enthalpies of formation of 2-, 3- and 4-cyanobenzoic acids were derived from their standard molar energies of combustion, in oxygen, at T=298.15K, measured by static bomb combustion calorimetry. The Calvet high temperature vacuum sublimation technique was used to measure the enthalpies of sublimation of 2- and 3-cyanobenzoic acids. The standard molar enthalpies of formation of the three compounds, in the gaseous phase, at T=298.15K, have been derived from the corresponding standard molar enthalpies of formation in the condensed phase and standard molar enthalpies for phase transition. The results obtained are −(150.7±2.0)kJ·mol −1 , −(153.6±1.7)kJ·mol −1 and −(157.1±1.4)kJ·mol −1 for 2-cyano, 3-cyano and 4-cyanobenzoic acids, respectively. Standard molar enthalpies of formation were also estimated by employing two different methodologies: one based on the Cox scheme and the other one based on several different computational approaches. The calculated values show a good agreement with the experimental values obtained in this work.