A case of Seckel's syndrome in which the results of hormonal tests and pneumoencephalography findings are worth relating is reported. The hormonal dosages have shown a disorder in the growth hormone activity with an over normal stimulus of the H.C.H. and its inefficacy over the N.E.F.A. (non esterefied free acids) curve. Pneumoencephalographic examination has shown cortico-cerebral atrophy reported for the first time in a case of Seckel's syndrome; this result may be considered as confirming the pathological findings reported by McKusick (microcephaly pongidae).