Pesticidal O-halogenocyclobutyl S-alkyl (di) thiophosph(on)ates of the formula ##STR1## in which x represents oxygen or sulphur,p represents zero, one or two,m represents zero, one or two,n represents 2, 3 or 4R.sup.1 represents alkyl, alkoxy which is optionally interrupted by oxygen or sulphur and can be substituted by halogen, or alkenyloxy, alkinyloxy, heterocyclyl-alkoxy or cycloalkoxy which is optionally substituted by alkyl and/or halogen,R.sup.2 represents alkyl which is optionally interrupted by oxygen or sulphur and can be substituted by halogen, or alkenyl, alkinyl or heterocyclyl-alkyl andR.sup.3 represents hydrogen or alkyl.