Enthalpies above 298 deg. K were determined for agcl to 1,400 deg. K and for agbr to 1,200 deg. K by copper-block calorimetry. Before melting, both compounds showed an anomalous increase in enthalpy, an effect associated with lattice defect formation. Melting points and heats of fusion were determined to be agcl, 730 deg. K and 2,945 cal/mole; agbr, 700 deg. K and 2,030 cal/mole. The heat capacity of both melted substances decreased with increasing temperature over the entire liquid ranges investigated. Enthalpies above 298 deg. K were tabulated at even temperatures along with derived entropy increments and heat capacity values. The results were combined with the known heats of formation and entropies at 298.15 Deg. K to obtain values of the heats and free energies of formation over the range 298.15 Deg. to 1,400 deg. K for agcl and 298.15 Deg. to 1,200 deg. K for agbr.