Abstract: 40 days after oral infection of rat with metacercariae of Pagumogonimus skrjabini, a few worms matured sexually in the abdominal cavity or worm-cysts formed in the lungs, while juveniles were detected in the muscles.60-90 days after infection, worm-cysts can not only be detected in the lungs, but also in the liver, mediastinum and abdominal wall, with matured or prematured worms and eggs. It is suggested that P. skrjabini could mature in rat and showed a phenomenon of polyor-ganotropism.By means of host-transfer with small juveniles, a part of them migrated to the lungs and matured, but the worms detected in muscles were still stunted (Figs. 1-4) .