Disclosed are 5-(vinylamino)pyryazole derivatives of formula I or pesticidally acceptable salts thereof (I) wherein, for example, W is ═N—, ═CH—, ═CR6— or ═C(NH2)-, R6 is halogen or haloalkyl, R1 is cyano, halogen, alkyl, haloalkyl or —CS—NH2, R2 is alkyl or cycloalkyl, R3 is alkyl, alkenyl, alkynyl, cycloalkyl, aryl, heterocyclyl, aralkyl, heterocyclylalkyl, —CO—O—R9, —CO—R10, —SO—R″, —SO2—R12; R9, R10, R11 and R12 are for example organic groups, R4 is halogen or —NH2, R5 is haloalkyl, haloalkoxy, halogen or —SF5, and n is an integer selected from 0, 1 or 2. These compounds cab be used for controlling pests, especially by treatment of domestic animals.