Rarely will see the emergence of liver fluke cercariae from bithyniid snails has not yet been studied. This study conducted investigate: 1) the pattern of emergence of cercariae of Opisthorchis viverrini (Wykoff et al, 1965) from field-infected B. (D.) s. goniomphalos, and, 2) the total number of cercariae released from each field-infected B. (D.) s. goniomphalos, under natural conditions.