Common variable immunodeficiency with an associated broad immunoglobulin (0.7%) deficit affecting all subclasses, was revealed in a 27-y-old previously healthy female, upon development of a severe pneumococcal meningitis. We report the third case of purulent meningitis complicating this primary immunodeficiency, and the second due to Streptococcus pneumoniae. Clinicians should maintain an elevated suspicion for congenital immunodeficiency, especially when observing adult patients with a negligible prior history.