Abstract: The heat capacity of 2,2-bishydroxymethyl-1,3-propanediol was measured over the temperature range 275 to 510 K by means of an automated adiabatic calorimeter. A solid-solid phase transition was found at 416.60 K. The enthalpy and entropy of the transition were determined to be 41.37 kJ tool~(-1) and 89.62 J K~(-1) mol~(-1) respectively. Using the enthalpy of the transition, the destroyed average hydrogen bond energy of the compound was deduced to be 9.69 kJ mol~(-1).