Abstract: This invention relates to novel organophosphorothiolates and phosphorodithioates of the formula: ##STR1## wherein R is a (C.sub.1 -C.sub.4) alkyl group;R' is a (C.sub.3 -C.sub.6) alkyl group;Y is an oxygen atom or sulfur atom;X is a halogen atom, a (C.sub.1 -C.sub.5) alkyl group, or a (C.sub.1 -C.sub.5) alkoxy group;m is an integer from 0 to 3; andA isA. a (C.sub.1 -C.sub.5) alkyl group optionally substituted with up to three halogen atoms;B. a (C.sub.5 -C.sub.6) cycloalkyl group;C. a (C.sub.7 -C.sub.10) aralkyl group, the aryl portion of which is optionally substituted with up to three halogen atoms, nitro groups, (C.sub.1 -C.sub.5) alkyl groups, or (C.sub.1 -C.sub.5) alkoxy groups; orD. an aryl group of the formula: ##STR2## WHEREIN X is a halogen atom, a nitro group, a (C.sub.1 -C.sub.5) alkyl group, or a (C.sub.1 -C.sub.5) alkoxy group; and m' is an integer from 0 to 3;To compositions containing them and to methods of using them to control pests.