An unusual, severe pneumonia probably caused by varicella-zoster virus is reported in a 19-year-old previously healthy man. The diagnosis was based on high titer of varicella-zoster antibodies in serum, and demonstration of varicella-zoster antigen from lung biopsy specimen. The uncommon feature in the pathophysiological course of the disease was the selective hypercarbia that responded well to bronchodilator therapy with theophylline. Furthermore, the patient had no skin manifestations during his illness.