We report a very unusual case of meningoencephalitis due to Listeria monocytogenes in a 7-month-old immunocompetent boy. Cerebrospinal fluid (CSF) culture was initially negative, but was positive on the seventh day. The disease was complicated by seizures and hydrocephalus managed with temporary ventriculostomy. The infant was discharged without obvious neurological sequelae after 30 days and developed without neurological or developmental sequelae at two years of age. Listeria is difficult to isolate and is not susceptible to third-generation cephalosporins commonly used for the empirical treatment of bacterial meningitis.