Human type II alveolar pneumonocytes were grown either as monolayers derived from a clone or as organotypic cultures of fetal lung. The type II cells in these cultures retained in their cytoplasm multilamellar bodies which were morphologically identical to similar organelles present in type II cells of intact human fetal and adult lung. A number of respiratory viruses infected the cells and produced a cytopathic effect in the cultures. Viral components were also detected in some of the infected cells. Adenovirus type 3, human coronavirus 229E, and rhinovirus types 2 and 9 produced new infectious virus, but influenza A and parainfluenza 3 virus apparently did not.