We discuss the cases of two patients affected with chronic eosinophilic pneumonia (CEP) pleurisy and eosinophilia in pleural effusion, not previously mentioned in the literature, to point out their peculiarity, to consider differential diagnosis and the effect of steroid therapy. Both patients, a 57-year-old man and a 55-year-old woman, were atopic: they had been suffering from allergic rhinitis and asthma for several years when they suffered sudden onset of cough, dyspnea and thoracic pain. This symptomatology persisted for more than 6 weeks. Chest radiography highlighted pulmonary infiltrates, not fixed in the first case, fixed in the second. The laboratory features revealed eosinophilia in peripheral blood and in pleural effusion. These data conformed to the criteria suggested by Jederlinic et al. for the diagnosis of chronic eosinophilic pneumonia. Tuberculosis had been present in the remote history of the second case; the repeated research for mycobacteria was negative, and no improvement was seen after antitubercular chemotherapy for one month. We excluded the diagnosis of allergic bronchopulmonary aspergillosis because of the absence of both precipitating antibodies against Aspergillus fumigatus and bronchiectasis. Neither vasculitis nor autoantibodies were found; possible drug-related correlations were excluded; culture data and serological researches for infections were negative in both cases; no involvement of other districts correlated to hypereosinophilia was evidenced. Clinical and radiological remission was obtained in both cases after steroid therapy for a month at the dosage of 1-2 mg/kg daily. No clinical recurrence was seen during a follow-up period of 6 months. Pleural effusion has already been reported in patients with CEP, while we have not found any references to pleural fluid eosinophilia in this disease; this finding has instead been already reported in patients affected with acute eosinophilic pneumonia or hypereosinophilic syndrome.