Twenty-eight specific-pathogen-free cats were inoculated with 14 to 50 metacercariae of Paragonimus kellicotti obtained from the hearts of naturally infected crayfish. Young flukes excysted in the intestine of cats and appeared in the peritoneal cavity from 1 to 14 days after inoculation (DAI) and in the pleural cavity from 5 to 23 DAI. Flukes penetrated the pulmonary parenchyma and formed hemorrhagic subpleural lesions within 5 weeks after inoculation. Marked eosinophilia developed between 2 and 12 weeks after inoculation. Fluke-containing pulmonary lesions were detected by radiography 3 to 4 weeks after inoculation. Lesions developed most frequently in the right caudal lung lobe. Clinical signs were mild and did not appear until 4 weeks after inoculation. Thereafter, cats appeared dull and coughed intermittently. One cat became dyspneic due to pneumothorax. Paragonimus eggs were first detected at the 34th DAI, using a fecal sedimentation technique.