Fungicidally active novel N-(3-chloro-1,2,4-oxadiazol-5-yl)-ureas of the formula ##STR1## in which R is alkyl, halogenoalkyl, or optionally substituted cycloalkyl, cycloalkylalkyl or aryl.
Fungicidally and bactericidally active 3-chloro-1,2,4-oxadiazoles of the formula ##STR1## in which R represents optionally substituted aryl or represents optionally substituted heteroaryl.