ABSTRACT: BACKGROUND: Idiopathic acute eosinophilic pneumonia is a rare disease. It presents with acute febrile illness, respiratory insufficiency, pulmonary infiltration and high eosinophil levels in Bronchoalveolar lavage fluid. Pathogenesis is not well understood, but related to the exposure to exogenous substances. CASE PRESENTATION: We present a case of 20-year-old man, who developed idiopathic acute eosinophilic pneumonia after smoking cigarettes and required intubation with mechanical ventilation. His symptoms resolve quickly after corticosteroids therapy. CONCLUSION: Idiopathic acute eosinophilic pneumonia should be considered in differential diagnosis of a patient with acute febrile respiratory illness, diffuse bilateral pulmonary infiltrates and recent modification in smoking habit.