High-temperature enthalpy increments of monazite-type EUPO4 and SMPO4 were measured by drop calorimetry in the temperature range 450-1570 K and the heat capacity was derived. The excess heat capacity C-exs was calculated by subtracting the lattice heat capacity, interpolated from isostructural LaPO4 (4f(0)) and GdPO4 (4f(7)) compounds. A good agreement was found with C-exs calculated from (estimated) crystal field energies. The heat capacity of PrPO4 was estimated with this approach. (c) 2006 Elsevier B.V. All rights reserved.