The densities of thermal vacancies and residual dislocations in bulk specimens of Fe-40 at.% Al have been investigated using differential dilatometry and X-ray diffraction. A large quenched-in vacancy concentration at temperatures above about 873 K was apparent from the decrease in average lattice parameter. This was correlated to a lowering of the effective enthalpy of vacancy formation from about 91 to 42 kJ mol-1, possibly caused by the presence of different types of point defect in lower- and higher- temperature regimes. The residual dislocations were found to have a major concentration on lcub100rcub planes at any given temperature. An increase in the dislocation density and a concurrent fall in the vacancy concentration was observed with a lowering of the quenching temperature from 1223 to 1073 K, indicating the possibility of vacancy annihilation at 1073 K.