True precocious puberty occurred in 16 children (15 girls and 1 boy) with non tumoral shunted hydrocephalus at a mean age of 6.8 years. They had mild clinical manifestations of precocious puberty, and the other pituitary functions were found to be normal. Except for one child, precocious puberty did not correlate with raised intracranial pressure or lack of cerebral drainage by the shunt. Growth was the main concern in this group as the predicted height fell at a mean value of 1.7 SD below the parental target height, and even more in children with myelomeningocele. This growth retardation is due to an early progression of bone age observed even prior to the appearance of breast or pubic hair. Therefore we suggest that these children might benefit from early treatment by an LHRH analogue as soon as precocious puberty occurs.