Saturated vapor pressure, ln(p/Pa) = (- 21316 +/- 511)/(T/K)+(41.64 +/- 0.11), and enthalpy of sublimation of orotic acid, triangle H-sub(m)0 (T-m) = 177 +/- 4 kJ/mol, were determined by means of Knudsen effusion mass spectrometry in the temperature range of 423 divided by 493 K. The computational approaches supported the experimental results reported. The theoretical estimation of the gas- phase enthalpy of formation for orotic acid was done with different working reactions used. (C) 2018 Elsevier B. V. All rights reserved.