We have investigated the relationship between cortisol and dehydroepiandrosterone (DHEA) levels and the immune response to mycobacterial antigens in peripheral venous blood, from a male population of active tuberculosis patients and age-matched healthy controls of the same sex (HCo). Peripheral blood mononuclear cells were cultured for 36 or 96 h with whole sonicated Mycobacterium tuberculosis (WSA) for measurement of proliferation, interferon gamma (IFN-gamma) and interleukin-10 (IL-10) in culture supernatants. Comparisons on the in vitro mycobacterial-driven immune responses demonstrated that TB patients had a higher IL-10 production, a decreased lymphoproliferation and a trend to reduced IFN-gamma synthesis, in relation to HCo. Active disease was also characterized by increases in the plasma levels of glucocorticoids (GC) and reduced concentrations of DHEA which resulted in a higher cortisol/DHEA ratio respect the HCo group. Plasma DHEA levels were positively correlated with IFN-gamma values. An inverse correlation was found between the cortisol/DHEA ratio and IFN-gamma levels. Novel evidence is provided showing that the balance between cortisol and DHEA is partly responsible for the immune perturbations seen in TB patients.