A 7-year-old female spayed Labrador Retriever was admitted to our hospital, because of cough with sputum. She was diagnosed as having canine eosinophilic pneumonia (CEP) based on blood eosinophilia, bronchial pattern and infiltrative shadow observed on thoracic radiography, bronchiolar obstruction and air-space consolidation predominantly affecting the right caudal lung lobe, as revealed by computed tomography (CT), predominant eosinophils in CT-guided fine needle aspiration and the clinical course. She exhibited a good response to steroid therapy, and the cough disappeared. The serum surfactant protein (SP)-A level increased with the aggravated symptom and decreased markedly with improvement compared with the C-reactive protein level and the number of eosinophils. We propose that serum SP-A level is a good biomarker in CEP.