While chlorine gas inhalation has previously been reported to cause temporary mucous membrane irritation, acute pneumonitis, pulmonary edema, and transient bronchospasm, there is controversy about the existence of long-term pulmonary sequelae. We report the case of a 25-year-old man in whom chronic, recurrent asthma developed after exposure to a chlorine gas leak in an enclosed space. His course since the exposure has been notable for frequent exacerbations necessitating chronic corticosteroid therapy and multiple hospitalizations. To our knowledge, the persistence of symptoms years after the exposure is unique in the literature.