Abstract A calculation of the energy of the giant dipole resonance is carried out using the wave function proposed by de-Shalit and Feshbach. The expectation value of the energy is shown to be determined by the differences in the mean square distances between neutron-neutron, proton-proton and neutron-proton pairs. The experimentally observed A − 1 3 dependence of the energy on nucleon number is shown to be a consequence of long-range pair correlations which vary as r −4 (as is the case for the ideal Fermi gas). An estimate based on the bulk Fermi gas correlation function, and neglecting Coulomb and other contributions, gives an energy of about twice the experimental value.