Novel 2-(2,2-difluorocyclopropyl)-acetic acid derivatives of formula I ##STR1## wherein A is oxygen or --NR.sub.1 --, B is C.sub.2 -C.sub.6 alkylene, D is oxygen, sulfur or --O--CH.sub.2 --, E is phenyl; phenyl substituted by from one to three substituents selected from the group halogen, C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.3 haloalkyl and C.sub.1 -C.sub.4 alkoxy; a five-membered aromatic heterocycle having from one to three hetero atoms selected from the group nitrogen, oxygen and sulfur; a five-membered aromatic heterocycle having from one to three hetero atoms selected from the group nitrogen, oxygen and sulfur that is substituted by one or two substituents selected from the group halogen, C.sub.1 -C.sub.4 alkyl and C.sub.1 -C.sub.3 haloalkyl; a six-membered aromatic heterocycle having from one to three nitrogen atoms; or a six-membered aromatic heterocycle having from one to three nitrogen atoms that is substituted by one or two substituents selected from the group halogen, C.sub.1 -C.sub.4 alkyl and C.sub.1 -C.sub.3 haloalkyl, L is halogen or methyl, n is 0, 1 or 2, and R.sub.1 is hydrogen, C.sub.1 -C.sub.4 alkyl, phenylthio or tolylthio, can be used as pesticides. Especially insects and arachnids can be controlled.