Abstract: The karyotype of Paragonimus westermani from Mayang Hill, Yueqing County of southern Zhejing Province, which is still an endemic area of paragonimiasis characterized by the finding of eggs of the parasite in sputum, was studied. The chromosome number is 2n = 22, and the karyotype consists of one pair of large-sized metaeentric, four pairs of medium-sized subtelocentrics, four pairs of small-sized submetacentrics and two pairs of small-sized metacentrics. In addition, spermatozoa were found in seminal receptacle in 97.8% of the adult worms, and the paragonimus metacercaria in Sinopotamon chekiangense was smaller, suggesting that this worm belongs to the bisexual type of P. westermami. Since tne worms under our observation were collected from the endemic area mentioned above, it was suggested that P. westermani with diploid pattern (or bisexual type) might cause typical pulmonary manifestations.