Abstract: Diploid and triploid types of Paragonimus westermani had similar cbromosomal karyotypes, however, they differed in chromosome c-band patterns. Two of three homologues of the triploid resembled those of the diploid in c-banding pattern, while the remaining chromosomes showed a different pattern. Heterogcneity in homologues was observed especially in chromosome Nos. 2, 3, 5, 6 and 7 (Fig. l, 2). In the diploid chromosome specimen, mitotic and meiosic phases were observed, while only the mitotic; phase was found in the triploid chromosome.