Several 2-aryloxymethyl-5-aryl-6-thioxo-[1,2,4]-triazolo [3,2-b] [1,3,4] thiadiazoles III have been synthesized from 2-amino-5-aryloxymethyl-[1,3,4] thiadiazoles I. The molluscicidal activity of few titled compounds has been evaluated against the snail Lymnaea acuminata. The LC50 slope, t-ratio heterogeneity and g-values have been determined and discussed.