Allergic bronchopulmonary aspergillosis (ABPA) is a well-known complication of cystic fibrosis (CF), with an estimated incidence of up to 11%. In patients with CF, the diagnosis of ABPA must be based on significant elevation of Aspergillus fumigatus (Af) antibody and total serum IgE, since it is common to already have other clinical and laboratory features of ABPA (Laufer et al., J Allergy Clin Immunol. 1984; 73:44-48). Once ABPA is identified in a patient, institution of corticosteroids is standard therapy. Invasive aspergillosis is a rare occurrence in patients with CF with or without ABPA, and has been reported in only one young adult who did not have ABPA (Giudotti et al., Am J Med Sci. 1982; 283:157-160). We present a case of a 15-year-old male with CF and ABPA who developed disseminated aspergillosis.