The interest for the surgical treatment of hydrocephalus has considerably increased in the last decade owning to the continuos development of the techniques for ventriculo-venous shunts. However, the occurrence of several complications lowered the initial enthusiasm of some neurosurgeons regarding this particular technique. Due to this fact we embarked upon a study for evaluation of the results in a series of 136 hydrocephalic children, operated upon between December 1958 and December 1965. Up to the present time (December-1967) a total of 72 children are alive, showing a compensated hydrocephalus and 30 patients died, being impossible to obtain a follow-up of the 34 remaining cases. After the analysis of the operatory conditions, of the complications and of the results, the folloying conclusions are withdrawn: 1) the ocurrence of pulmonary tromboembolic complications is quite rare after ventriculoatrial shunts, justifying the use of this technique for the treatment of hydrocephaly till others forms of treatment are available; 2) periodic cardiologic examinations should be performed in patients submitted to ventriculo-venous shunts in order to prevent right cardiac insuficiency; 3) the prevention of infectious complications and selection of the cases are fundamental for better post-operative results; 4) the physician responsible for treatment of hydrocephalic patients should warn the parents regarding the possibility of new sirguical interventions and be ready to re-operate as many times as necessary; 5) there is not justifycable the replacement of the atrial tube when its extremity reaches the level of the fourth thoracic vertebra; 6) there is not correct the assertion that an shunt has to remain always with the drainage process working fully; 7) in order to evaluate the prognosis of the mental development of the hydrocephalic patients, a group of data has to be considered as a whole, namely the neurological examination, cranial transilumination, etiology of the disease, electroencephalo-graphic tracings, Gesell test and, if possible, the measurement of the cerebral mantle; 8) a normal psychological development (IQ greater than 85) can be expected in about 40% of the patients with controled hydrocephalus.