Four adults had varicella pneumonitis. All developed respiratory symptoms within a week of the exanthem. Cough and/or dyspnea, cyanosis and chest pain were common. Radiological signs of disease were more marked than physical signs. A slight polymorphonuclear leukocytosis and normal sputum culture were usual. One man with mild symptoms recovered. Two women, one pregnant, had severe symptoms and died. A second man succumbed to secondary bacterial pneumonia. The lungs in fatal cases showed interstitial pneumonitis with mononuclear cell infiltrate, focal areas of necrosis, and acidophilic inclusion bodies in two cases. Patients received oxygen, antibiotics and, in one instance, corticosteroid therapy. The value of antibiotics and corticosteroid treatment is questionable. Use of gamma globulin in preventing varicella pneumonitis is mentioned and residual pulmonary changes are discussed.