Isobaric heat capacities of C60(OH)40 and C70(OH)12 fullerenols were measured using adiabatic calorimetry in the temperature range of 0–320K along with standard thermodynamic functions: Sm, [Φm(T)−Φm(0)] and [Hm(T)−Hm(0)]. Furthermore, the molar entropy of formation and the molar third law entropy of C60(OH)40 and C70(OH)12 in crystalline state at 298.15K were calculated.