Primary varicella infection is uncommon in adults, but carries a higher rate of morbidity and mortality than in children. Pneumonia is the most common complication of primary varicella infection in adults. However, varicella pneumonia complicated with acute respiratory distress syndrome (ARDS) is very rare. We report a case of ARDS secondary to varicella pneumonia in a 26-year-old man with primary varicella. The patient was otherwise healthy and had no evidence of human immunodeficiency virus infection. The initial chest radiograph showed bilateral reticulonodular infiltrates, which quickly evolved to diffuse alveolar consolidations. Arterial blood gas analysis revealed a ratio of arterial partial pressure to fraction of inspired oxygen of 87. Abnormal liver function and thrombocytopenia were also noted. Treatment consisted of mechanical ventilatory support and intravenous administration of acyclovir. His pulmonary condition gradually improved and he was successfully weaned from the ventilator 1 week later. He was discharged on the 15th hospital day with a favorable outcome. His pulmonary function improved progressively, with normal spirometry and lung volumes, but persistent mild impairment of diffusing capacity, 6 months after discharge.