Adult patients with rheumatic arthritis and other rheumatic disorders show inappropriate cortisol secretion and peculiar CRH promoter gene polymorphisms. So far, no data are available about this topic in children with juvenile idiopathic arthritis (JIA). We have studied a series of 13 prepubertal patients (10 female, 3 male) affected with oligoarticular JIA (o-JIA) without clinical and biological signs of disease activity (ESR and IL-6). ACTH plasma concentrations were significantly increased at 8 a.m. in o-JIA patients, whereas no differences were found in cortisol plasma concentrations. The ACTH/cortisol ratio was significantly increased in o-JIA patients with respect to the normal population both at 8 a.m. and at noon. DHEAS and testosterone plasma concentration did not statistically differ in the two populations. The genetic study was aimed at defining the prevalence of polymorphisms A1 and A2 in o-JIA patients, but we failed to find allelic or genotypic differences. Our study suggests the presence of a partial resistance to ACTH with a dysregulated pattern of secretion also in inactive o-JIA patients. These preliminary data need further confirmation in larger pediatric studies.