An autopsy case of an 18 month old male infant with measles infection is reported. An autopsy revealed generalized lymphadenopathy, splenomegaly and hyperplastic thymus. Histologically, there were many Warthin-Finkeldey cells (WFC) in hyperplastic lymphoid tissues. Although viral particles and inclusions were not detected electronmicroscopically, the infection of measles virus was detected in WFC by immunofluorescent technique using anti-measles antibody. Warthin-Finkeldey cells were morphologically and immunohistochemically divided into two groups. The first type was WFC appearing in the germinal centers of lymphoid tissue, revealing many large nuclei and B cell markers. The second type was WFC appearing in the interfollicular areas and thymus, showing many small hyperchromatic nuclei and T cell markers. The data indicate that there might be a morphologic and immunophenotypic heterogeneity in WFC.