In the present study, we investigated whether synaptic plasticity changes in the hippocampus of depressive-like socially stressed rats could be reversed by chronic antidepressant treatment. To that end, rats were either defeated and subsequently individually housed or subjected to control treatment followed by social housing. After a period of at least 3 months, rats were either treated chronically with imipramine (20 mg/kg per day, per os for at least 3 months) or the solvent solution (i.e. water). Then, long-term potentiation and depression were measured in the CA1 region of the hippocampus in vitro. Chronic imipramine treatment partially restored the attenuated induction of long-term potentiation and suppressed the facilitation of long-term depression-induction in socially stressed rats. The altered synaptic plasticity after social stress is discussed in relation to cognitive deficits and hippocampal changes that are observed in depressive patients.