Infection by unusual microorganisms can be one of the clinical manifestations of primary immunodeficiency (PID). We report on a four-month-old child with pneumonia caused by the fungus Acremonium kiliense as the first clinical manifestation of chronic granulomatous disease. We emphasize the importance of an active search for unusual organisms in immunodeficient patients, and a precise diagnosis and early institution of specific treatment against such microorganisms for the reduction of the morbidity and mortality of these patients.