Human infection with Lophomonas blattarum is extremely rare. The clinical manifestations of 45 cases of bronchopulmonary L. blattarum infection occurring in China, including one case diagnosed and treated at the authors' hospital, are described. The most common manifestations included fever, cough with expectoration, chest stuffiness or shortness of breath, bronchiectasis and pulmonary abscess. A course of metronidazole treatment lasting 14-38 days was effective in controlling the disease. The diagnosis of L. blattarum infection should be based on one or more of bronchoscopic brush smear, bronchoscopic biopsy smear and bronchoalveolar lavage.