Idiopathic chronic eosinophilic pneumonia is a rare disease first described by Carrington 30 years ago. The cause is unknown. As illustrated by the case described in this report, most cases occur in asthmatic patients in the fifth decade of life. Cardinal features are respiratory symptoms, altered general status, laboratory evidence of inflammation, blood eosinophilia in most cases, and x-ray images showing the presence of infiltrates in both lungs. Diagnosis can be confirmed by detection of eosinophils in broncho-alveolar lavage fluid. Extrapulmonary involvement is uncommon and is suggestive of Churg and Strauss syndrome. In atypical cases, diagnosis requires histological study demonstrating infiltration of interstitial tissue and alveolar spaces. Differential diagnosis can be difficult since several disorders identified within the last 10 years are nosologically similar, e.g. acute eosinophilic pneumonia. In many cases, diagnosis is based on response to corticosteroid treatment which is highly effective on idiopathic chronic eosinophilic pneumonia. Frequent recurrence leads to corticosteroid dependence in 20 to 30% of cases.