Pesticidal mixtures comprising, as active components, 1) a malonodinitrile compound selected from compounds I-1 to I-8 CF2HCF2CF2CF2CH2C(CN)2CH2CH2CF3 (compound I-1; name: 2-(2,2,3,3,4,4,5,5-octofluoro-pentyl)-2-(3,3,3-trifluoro-propyl)-malononitrile); CF3(CH2)2C(CN)2CH2(CF2)5CF2H (compound I-2; name: 2-(2,2,3,3,4,4,5,5,6,6,7,7-dodecafluoro-heptyl)-2-(3,3,3-trifluoro-propyl)-malononitrile); CF3(CH2)2C(CN)2(CH2)2C(CF3)2F (compound I-3; name: 2-(3,4,4,4-tetrafluoro-3-trifluoromethyl-butyl)-2-(3,3,3-trifluoro-propyl)-malononitrile); CF3(CH2)2C(CN)2(CH2)2(CF2)3CF3 (compound I-4; name: 2-(3,3,4,4,5,5,6,6,6-nonafluoro-hexyl)-2-(3,3,3-trifluoro-propyl)-malononitrile); CF2H(CF2)3CH2C(CN)2CH2(CF2)3CF2H (compound I-5; name: 2,2-bis-(2,2,3,3,4,4,5,5-octafluoro-pentyl)-malononitrile); CF3(CH2)2C(CN)2CH2(CF2)3CF3 (compound I-6; name: 2-(2,2,3,3,4,4,5,5,5-nonafluoro-pentyl)-2-(3,3,3-trifluoro-propyl)-malononitrile); CF3(CF2)2CH2C(CN)2CH2(CF2)3CF2H (compound I-7; name: 2-(2,2,3,3,4,4,4-heptafluoro-butyl)-2-(2,2,3,3,4,4,5,5-octafluoro-pentyl)-malononitrile); or CF3CF2CH2C(CN)2CH2(CF2)3CF2H (compound I-8; name: 2-(2,2,3,3,4,4,5,5-octafluoro-pentyl)-2-(2,2,3,3,3-pentafluoro-propyl)-malononitrile); and 2) one or more compounds II selected from group A consisting of organo(thio)-phosphates, carbamates, pyrethroids, growth regulators, nicotinic receptor agonists/antagonists compounds, GABA antagonist compounds, macrocyclic lactone insecticides, METI I acaricides, METI II and III compounds, uncoupler compounds, oxidative phosphorylation inhibitor compounds, mixed function oxidase inhibitor compounds, sodium channel blocker compounds and others, all as defined in the description, in synergistically effective amounts, use of these mixture for combating insects, arachnids or nematodes in and on plants and for the protection of seeds, and for treating, controlling, preventing or protecting a warm-blooded animal or a fish against infestation or infection by parasites.