We report the case of a patient with a history of chronic bronchiectasis that presented with new onset fatigue, shortness of breath, peripheral blood eosinophilia and infiltrates on chest radiograph. Eight days previously, she was prescribed inhaled colistimethate sodium 75 mg bid to prevent exacerbations of her respiratory condition. To our knowledge, our case is the first to show the clinical and radiologic features of inhaled-colistimethate-induced pulmonary eosinophilia. It also shows the rapid resolution of its features following treatment with oral corticosteroids. Eosinophilic lung reaction to inhaled colistin is rarely reported in the literature. Clinicians should be aware of this possible side effect.