The present paper reports a model of stress induction, based on electrical stimulation of the brain in normal Wistar rats. Stress-related stimulation of the hypothalamic-pituitary-adrenal axis produced a rise in circulating corticosterone levels that correlated significantly with the impairment of some immunological parameters, such as delayed hypersensitivity reactions to dinitrofluorobenzene and to sheep red blood cells, together with changes in splenocyte proliferation and phagocytic activity of peritoneal macrophages. This experimentally elicited stress in the rat is proposed as a suitable model of immunosuppression that could be used for the evaluation of drugs with potential immunomodulatory properties.