The heat capacity of LaMnO3 was measured by differential scanning calorimetry (DSC) in the (150-760) K range and by alternative current calorimetry (ACC) in the (77-250) K range. The heat capacity curve showed two thermal anomalies due to a structural phase transition at 735 K and a magnetic transition at 140 K. The enthalpy and entropy changes accompanying the magnetic transition are 220 J mol(-1) and 1.70 J K-1.mol(-1), whereas those for the higher temperature phase transition were estimated to be 3.36 kJ mol(-1) and 4.2 J K-1 mol(-1). The non-transitional heat capacity of LaMnO3 was calculated by multiple regression analysis and is given by the following expressions. C-p,C-m = 2.82 + 0.874T - 6.93 x 10(4)/T-2 + 3.98 x 10(-7)T(3) - 3.31 x 10(-2)T(3/2) (77 less than or equal to T less than or equal to 298) C-p,C-m = 96.73 + 5.36 x 10(-2)T - 8.82 x 10(5)/T-2 (298 less than or equal to T less than or equal to 760).