The eight solid complexes of zinc with L-alpha-methionine or L-alpha-histidine were prepared. The constant-volume combustion energies of the complexes, Delta(c,coor)E, at 298.15 K have been determined by using a precision rotating-bomb calorimeter. The standard enthalpies of combustion, Delta(c,coor)H(theta), and standard enthalpies of formation, Delta(f,coor)H(theta), have been calculated for these complexes.