Novel pesticidal compositions are comprised of a 2,2-dimethyl-3-(substituted ethyl)cyclopropanecarboxylic acid ester as the active ingredient, said cyclopropanecarboxylate having the structural formula: ##STR1## wherein X, Y and Z are the same or different and at least two of same are chlorine or bromine, with the remaining one being hyrogen, methyl, chlorine or bromine; R is an alcohol residue represented by one of the following structural formulae (II), (III), (IV) and (V): ##STR2## where A represents hydrogen, cyano, ethynyl or thiocarbamoyl; Q is hydrogen, chlorine, bromine, fluorine, methyl or trifluoromethyl; R.sup.1 is propargyl or benzyl; R.sup.2 represents 2-halogeno-3-phenyl-1-propen-1-yl, (dihalogenovinyloxy)phenyl, benzylphenyl, phthalimido, thiophthalimido, di- or tetrahydrophthalimido or dialkylmaleido; R.sup.3 represents allyl, 2,4-pentadienyl, propargyl or benzyl.