Sea-blue histiocytosis is one of the six types of Niemann-Pick disease. It is characterized by childhood onset of hepatosplenomegaly, lack of neurological involvement and diminished sphingomyelinase activity. Pulmonary system is rarely involved sea-blue histiocytosis. In this paper, we present a 39-years-old male who had previously diagnosed as sea-blue histiocytosis at the age of 15. He was admitted to our clinic due to productive cough, hemoptysis, fever and weight loss. His symptoms did not resolve with the antibiotic treatment and further investigations revealed pulmonary involvement of sea-blue histiocytosis. After diagnostic bronchoalveolar lavage, his symptoms were improved, interestingly. This rare entity was discussed with literature survey.