Abstract: A comparative study was performed in detail on the c-band pattern of diploid and triploid types of Paragonimus westermani by using BSG method. The result revealed that both typas of P. westermani possessed the identical c-band pattern and c-band polymorphism. Thus the authors considered that the triploid type of P. westermani might be an autotriploid. The polymorphism of c-band pattern in diploid and the combination of homologous chromosomes with c-band polymorphism in triploid were reported for the first time (Figs.1-4).