Under the conditions assumed both by Forster in his resonance-transfer theory and by Kennard and Stepanov in their theory of a universal relation between fluorescence and absorption, the rates of transfer between two chromophores k and l are related by Fl-k/Fk-l = exp[-(Delta G(k) - Delta G(l))/k(B)T)], where the energies Delta G(j) are the free energies of excitation relating to the vibrational and other bath states interacting with the chromophore. They are dominated by, but not identical with, the 0-0 transition energies of the two chromophores. We show that Delta G(k) - Delta G(l) can be computed reliably with Forster＇s overlap integral approximation only when the Kennard-Stepanov relation is obeyed for both chromophores. We examine the extent to which approximations to Forster-Dexter transfer agree with this detailed balance result and the implications of the result for multichromophore systems.