We report the case of a 54-year-old woman with aplastic anemia, who developed transient pulmonary infiltrates following intravenous infusion of rabbit antithymocyte globulin (ATG) for 3 days. There was no other explanation than the infusion of ATG for the infiltrates. Rechallenge with ATG induced the recurrence of opacities on the chest radiograph. Although rarely involved with only 4 previous reports, ATG should be included in the list of drugs capable of inducing pulmonary infiltrates.