Rodenticidal compositions containing as the active ingredient novel 1-(3-pyridylmethyl)-3-(4'-substituted-phenyl or -naphthyl)ureas and their acid addition salts. The 4'-substituent may be nitro, cyano, trifluoromethyl, butyryl, thiocyano, alkylthio, phenylsulfonyl or diethylsulfonamide.