Experimental completion of the life-cycle of Paragonimus westermani (Trematoda: Troglotrematidae) (diploid type) from egg to adult has been achieved in the laboratory for the first time. A dog was fed metacercariae of P. westermani from naturally infected freshwater crabs, Geothelphusa dehaani. The adult flukes were recovered and their eggs were incubated in water at 28°C, hatching after 20 days. Laboratory reared marsh snails, Semisulcospira libertina, were exposed to miracidia from embryonated eggs. One of 47 snails became infected with a large number of 2nd generation rediae containing fully mature cercariae 245 days after exposure. Paragonimus-free crabs (G. dehaani) were then infected with the intramolluscan larvae. Of the 40 crabs examined 34–70 days after infection, 17 were infected with a total of 84 metacercariae. A cat and 4 dogs were fed with 55 metacercariae obtained. Eighty to 100 days later, a total of 40 flukes was recovered; 39 flukes were adults with eggs in their Uteri.
