Thirty-nine cases of pulmonary paragonimiasis due to Paragonimus westermani were identified in Manipur, India. Recurrent haemoptysis, often increased on exertion, was the most common symptom. The clinical features and radiological appearances simulated pulmonary tuberculosis and 23 cases were treated for tuberculosis for varying periods before the final diagnosis. Young males aged 11 to 30 years comprised two-thirds of the cases. The disease was acquired by eating raw or improperly cooked crabs (Potamon deham). Intradermal tests (IDT) employing a saline extract of adult Paragonimus were a simple and reliable method of detecting present or past infection. Erythema of large size even without wheal and pseudopodia may indicate a positive IDT. Charcot-Leyden crystals (CLC) were detected in all sputum samples positive for Paragonimus ova. In patients (four) presenting with pleural effusion, Paragonimus ova were not present in the sputum, stool or pleural fluid. Bithionol (2,2'-thiobis [4,6-dichlorophenol]) orally, 40 mg/kg body-weight/day, 10 to 25 doses, cured all cases and, except in one, side effects were minimal. Relapse in one patient after six months' treatment was apparently cured by a second course of Bithionol.