Abstract: 1. The monthly density of snails from January through December of 1982 were found to be 41±23-156±99/33.3cm2.2. The P. skrjabini larvae incidence of snail from October of 1982 to April of 1983 were 0.45% (0.29-0.85%), and their intensity of infection were 2.4(2-3.5) for rediae and 16.1(5-3.6) for cercariae/positive snail. The positive snails for P. skrjabini are sporodically distributed in the natural focus.Thus, on the basis of our findings, it is suggested that epiderniological survey of pagumogonimiasis by examining the first intermediate host, Pseudobythinella shimenensis, to determine the natural foci may be carried out at any month of the year.