Disclosed are 5-(vinylamino)pyryazole derivatives of formula I or pesticidcally 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-N H2, R2 is alkyl or cycloalkyl, R3 is alkyl, alkenyl, alkynyl, cycloalkyl, aryl, heterocyclyl, aralkyl, heterocyclylalkyl, -CO-O-R9, -CO-R10, -SO-R', -S02-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.