We study the effects of electron-electron interactions on the localiza
tion properties of electronic states in the random-dimer model. We sho
w at the mean-field level that, although disorder or interactions sepa
rately do not destroy the dimer resonances, the combination of both ca
n lead to localization. However, numerical evidence suggests that the
localization length of the electronic states is larger than the typica
l size of the polymers in which this model is relevant.