2-Phenoxypropionic acid cyanamides of the formula ##STR1## have a useful selective herbicidal activity against weeds, preferably grass weeds, in crops of useful plants.In this formulaR is hydrogen, C.sub.1 -C.sub.4 alkyl, C.sub.3 -C.sub.4 alkenyl, C.sub.3 -C.sub.4 alkynyl or C.sub.2 -C.sub.4 alkoxyalkyl, andT is a radical ##STR2## wherein A is oxygen or sulfur,X is fluorine, chlorine, bromine, iodine or trifluoromethyl,Y is hydrogen, fluorine, chlorine, bromine or trifluormethyl, andZ is nitrogen or the methine bridge.