In a calorimeter with a static bomb and an isothermal shield, the energy of combustion of the cyanocobalamin has been measured at 298.15 K. Physico-chemical methods established the products of combustion of cyanocobalamin in the conditions of calorimetric experiment. The enthalpy of combustion ÃŽâ€cH° and the thermodynamic parameters ÃŽâ€fH°, ÃŽâ€fG° of the cyanocobalamin at T = 298.15 K and p = 0.1 MPa have been calculated. Thermodynamic parameters ÃŽâ€fH°, ÃŽâ€fS° were determined and used to calculate the enthalpy of formation of cyanocobalamin.