The present study points out that the CHRONIC RENAL FAILURE (CRF) represents a situation of decreased adrenal function: at least for delta 5 Steroids which are markedly reduced when compared with normal subjects. Peripheral plasma levels of Pregnenolone (delta 5 P) ranged in CRF between 190 and 860 pg/ml; Dehydroepiandrosterone-sulphate (DHA-S) 0.1-2.2 ng/ml and Dehydroepiandrosterone (DHA) 200-3100 pg/ml. Cortisol was in the normal range or slightly elevated (70-175 ng/ml). A significant correlation between basal concentration and the time of dialysis was observed. It is interesting to notice how the phase levels of delta 5 P, DHA-S and DHA are reduced ad from the beginning of the haemodialysis treatment and that during such a treatment a further progressive decrease occurs reaching concentrations with are similar to those found in pre-puberty. This phenomenon appears to be the evidence of a progressive metabolic involution of the adrenal gland due to the exhaustion of enzymatic activities and of receptorial structures. Furthermore, these results suggest speculation on interrelationship between adrenal and gonadal activity in these patients.