The object of this investigation is to resolve the discrepancy between theory and experiment for the case of heat transfer during film condensation of liquid metal vapors. Calculations from kinetic theory show that with liquid metals a significant thermal resistance can exist at the liquid-vapor interface. This resistance increases with decreasing vapor pressure and is dependent on the value of an accommodation coefficient, named the “condensation coefficient” in this case. Experimental work verifying this hypothesis of a liquid-vapor interfacial resistance is presented here for mercury condensing at low pressures in the absence of noncondensable gases on a vertical nickel surface.