The authors report 6 cases of colloid cyst of the third ventricle treated with unilateral ventriculo-atrial shunt and followed up 14 to 3 years. Today the diagnostic of these cysts is safer with C.T.-Scan and M.R.I.; in the 6 cases hydrocephalus was reduced and the volume of the cysts did not increase on C.T.-Scan controls. Nowadays the stereotactic approach seems to be safer than direct surgery but is not always a radical treatment and can be insufficient to treat hydrocephalus. We think that ventricular shunt can be a good alternative as a first and definitive treatment.