Both babies were 5-month-old boys who had no symptomatic disorders and were found dead in bed. Their main macropathology was inflated heavy lungs with patchy bleedings. One case revealed a pulmonary histopathological finding suggestive of viral infection; analysis of the intrabronchial fluid determined the presence of adenovirus DNA. Pulmonary histopathology in the second case was a feature of early inflammatory reaction involving focal necrosis with some neutrophil infiltration and many intra-alveolar macrophages containing gram-positive cocci; venous blood culture identified Staphylococcus aureus. Findings provided significant support for the presence of pathogenic microorganisms in sudden infant death. Figures and 19 references (Author abstract modified)