Chronic enteroviral meningoencephalitis, most commonly caused by echoviruses, can particularly be seen in agammaglobulinemic patients. In spite of the fact that no specific treatment for enteroviral infections exists, pleconaril is an antiviral drug reported to be efficient against enteroviral infections in infants and adults. We present a case of a 42-year-old male, previously diagnosed with common variable immunodeficiency, who presented with severe chronic meningoencephalitis caused by Echo virus 6 and was successfully treated with pleconaril. Enteroviruses usually cause mild symptoms, but some strains can cause life-threatening conditions especially in immunocompromised patients. Although pleconaril production is unprofitable due to the rarity of severe disease, our effective treatment should encourage further availability of pleconaril.