In patients with chronic eosinophilic pneumonia (CEP), dramatic improvements are seen in response to corticosteroid therapy; however, relapse is common after treatment has ceased. The optimal duration of corticosteroid therapy remains unclear.In a randomised, open-label, parallel group study, eligible patients with CEP received oral prednisolone for either 3 months (3-month group) or 6 months (6-month group), followed by 2 years observation. All patients were treated with an initial dose of prednisolone of 0.5 mg·kg −1 ·day −1, which was then tapered and discontinued at either 3 or 6 months. The primary end-point was relapse during the follow-up period.In the final analysis, there were 23 patients in the 3-month group and 21 patients in the 6-month group. All patients showed a good response to prednisolone treatment. There were 12 (52.1%) relapses in the 3-month group and 13 (61.9%) relapses in the 6-month group. No significant difference was found in the cumulative rate of relapse ( p=0.56). All relapse cases showed improvement upon resumption of prednisolone treatment.No difference was observed in the rate of relapse between the 3-and 6-month prednisolone treatment groups for patients with CEP. @ERSpublications Short-term, 3 month, prednisolone treatment is a therapeutic option for chronic eosinophilic pneumonia