Newcastle disease virus (NDV)-induced damage to the embryonic chicken trachea, the tracheal explants, and red blood cells (RBCs) was studied by scanning electron microscopy. In the tracheae, NDV caused deciliation and depletion of the epithelial cells. In the tracheal explants, the same pathologic changes could be seen within 6 hr of virus infection. In RBCs, a perforation and a change in surface morphology were observed.