BACKGROUND Idiopathic chronic eosinophilic pneumonia (ICEP) is one of the hypereosinophilic lung diseases. BACKGROUND ICEP is a rare disease of unknown cause that combines non-specific respiratory and general symptoms with predominantly peripheral radiological infiltrates. The presence of blood and alveolar eosinophilia points strongly to the diagnosis. ICEP is very sensitive to systemic corticosteroids but relapses are common following stopping treatment or reducing the dose. A background of asthma is commonly found and many patients with ICEP develop severe asthma which, together with the relapses, often necessitates prolonged systemic corticosteroid treatment. The long term prognosis, however, remains excellent. CONCLUSIONS The role of inhaled corticosteroids in non-asthmatic patients remains uncertain and should be evaluated further. The links between asthma and ICEP could lead to a better understanding of the mechanisms underlying hypereosinophilic lung diseases. CONCLUSIONS ICEP is a rare disease that is important to recognise on account of its potentially disabling nature and its good response to corticosteroid treatment though long term maintenance is some times necessary on account of relapses or the development of severe asthma.