We encountered three cases of paragonimiasis westermani caused by ingestion of Chinese freshwater crabs. All patients are Chinese living in Japan who had a history of eating raw Shanghai crabs at the Chinese restaurant owned by one of them. A few months later they complained of cough, chest pain and dyspnea. On examination, their peripheral blood showed a remarkable increase in eosinophils. Chest radiographs revealed the presence of pleural effusion in all cases, and of pneumothorax in one. Pleural fluid obtained from two cases showed an increased number of eosinophils, an elevated LDH, and a decreased glucose level. Paragonimus westermani was determined in a positive serum antibody test. The patients were treated with praziquantel for 3 days at a daily dosage of 75 mg/kg and their symptoms were relieved, but one case needed additional treatment with praziquantel for 3 days at a daily dosage of 50 mg/kg because of sustained pleural effusion and a persistently high antibody titer. Most cases of paragonimiasis found in Japan have been sporadic and individual, but three cases occurring close to each other in both distance and time have recently been reported. Such multiple infections are likely to increase because of the gourmet food boom and the internationalization of eating habits. Paragonimiasis must be kept in mind in the differential diagnosis of cases of pleural effusion with eosinophilia. We would therefore like to emphasize the importance of the detection of parasite-specific antibodies and of careful history-taking from patients.