FIELD: agriculture.SUBSTANCE: invention relates to agriculture. The aqueous herbicidal composition comprises at least one herbicidal phenoxy acid, its agriculturally acceptable salt or derivative and a surface-active adjuvant, wherein the said surface-active adjuvant comprises at least one surface-active alkyl amide propyl dialkylamine of the formula , where R represents an acyl group with a straight or branched, saturated or unsaturated chain containing from 6 to 22 carbon atoms, n is 3, and Y and Y independently from each other represent an alkyl group containing from 1 to 4 carbon atoms, or (AO)sH, where AO is an alkylene oxy group containing from 2 to 4 carbon atoms, preferably 2 carbon atoms, and the average value s is in the range from 1 to 10, preferably from 1 to 4, most preferably from 1 to 2, with the provison that at least one and preferably both groups Y and Y represent an alkyl group containing from 1 to 4 carbon atoms or its salt, or a quaternary derivative of the compound (I) of the formula , where R represents an acyl group with a straight or branched, saturated or unsaturated chain containing from 6 to 22 carbon atoms, preferably from 6 to 18, more preferably from 6 to 14, most preferably from 6 to 10 carbon atoms n is 3, preferably 3 Y and Y independently from each other represent an alkyl group containing from 1 to 4 carbon atoms, or (AO)sH, where AO is an alkylene oxy group containing from 2 to 4 carbon atoms preferably 2 carbon atoms, and the average value s is in the range from 1 to 10, preferably from 1 to 4, and most preferably from 1 to 2, with the proviso that at least one and preferably both groups Y and Y represent an alkyl group containing from 1 to 4 carbon atoms R2 represent a C1-C4 alkyl group, and X- represents an anion. The composition is prepared by mixing its components and is applied to the unwanted vegetation.EFFECT: invention enables to improve the efficiency of the composition.25 cl, 8 tbl, 2 exИзобретение относится к сельско