The invention relates to aminoacetonitrile compounds of the formula ##STR00001## wherein m is 1, 2 or 3; R.sub.1 is C.sub.1-C.sub.4-alkyl, C.sub.1-C.sub.4-alkoxy, C.sub.1-C.sub.4-haloalkyl, C.sub.1-C.sub.4-haloalkoxy or halogen, whereby the substituents may respectively be identical or different, if m is greater than 1; and R.sub.2 is C.sub.1-C.sub.4-haloalkyl; and optionally enantiomers thereof; and the use of aminoacetonitrile compounds of formula I in the control of endoparasites, especially helminths, in warm-blooded productive livestock and domestic animals.