An unusual case of Niemann-Pick disease type C is reported. The disease was first manifested in utero with hepatomegaly and ascitis. At the age of 3 months, respiratory signs were noted due to diffuse alveolar and interstitial pneumonia. Both bronchoalveolar lavage and blood serologic studies revealed respiratory infection by respiratory syncitial virus and Chlamydia trachomatis. These concomitant infections delayed the diagnosis of Niemann-Pick disease which was finally made by the electronic microscopic studies of liver biopsy and bone marrow specimens. Type C was identified by biochemical characterization of lipid accumulation in hepatocytes and by lipid enzyme profiles obtained from cutaneous fibroblast cultures. The child died at the age of 6 months from respiratory failure. Post mortem examination of the lung showed the presence of numerous overloaded alveolar macrophages in the alveolar spaces and walls. The severity of the lung issue disease is unusual in type C Niemann-Pick disease, in which neurologic involvement is usually the main prognosis factor.