A 3-month-old female patient presented with a meningomyelocele at the lumber region associated with congenital hydrocephalus. She underwent ventriculoperitoneal (V-P) shunt surgery using the Sophy system. The shunt system was replaced due to a malformation. Following replacement, the patient presented with cerebrospinal fluid (CSF) eosinophilia at the age of 8 months. The eosinophilic granulocytosis of the CSF improved dramatically following systemic prednisolone administration. CSF eosinophilia without accompanying inflammation or pyrexia in the present case may have resulted from an allergic response to a foreign material such as the silicone tube pressure valve of the Sophy system or the sutures rather than bacterial or fungal infection. Based on our results, we believe that some patients may experience CSF eosinophilia following postoperative V-P shunt due to an allergic reaction to the shunt equipment. Prompt steroid treatment can produce spontaneous regression in such cases.