The authors report an adaptation of the ventriculo-auriculostomy, with the Holter valve, for cases of bilateral obstruction of the foramina of Monro and for bilateral subdural fluid collection. Two catheters of silicone are placed into the lateral ventricles or in the subdural spaces, through para-median burr openings made in the posterior parietal area; these catheters are connected to a T-shaped tube (Kehr tube), which in turn is attached to the end of a Holter valve; the other operative stages are the same as in the conventional ventriculo-auriculostomy. With this procedure three patients have been operated on: two with craniopharyngioma and one with bilateral subdural fluid collection. The results were good.