Leptospirosis is a re-emerging zoonosis occurring as large outbreaks throughout the world caused by Leptospira interrogans. The incidence of pulmonary involvement in leptospirosis has been reported to be increasing in the last years, affecting up to 70% of the patients. Alveolar hemorrhage presented as dyspnea and hemoptysis is the main pulmonary manifestation. The emergence of massive hemoptysis and acute respiratory distress syndrome has characterized the recent changes reported in the clinical patterns of leptospirosis. The pulmonary involvement has been emerged as a serious life threat, becoming the main cause of death due to leptospirosis in some countries. In this review we present the main clinical and pathological manifestations of pulmonary involvement in leptospirosis, with special focus on recent data concerning the pathophysiological mechanisms underlying lung injury.