Pneumonia is a rare but serious complication of varicella in adults. We report a case of a previously healthy 32-year-old man with varicella pneumonia that was complicated by acute respiratory distress syndrome. He was treated successfully with acyclovir and intravenous immunoglobulin in addition to mechanical ventilation. We conclude that intravenous immunoglobulin, in combination with acyclovir, is a safe and probably effective therapy for adult varicella pneumonia that is complicated by acute respiratory distress syndrome.