diff --git a/dspace/config/controlled-vocabularies/controlledvocabulary.xsd b/dspace/config/controlled-vocabularies/controlledvocabulary.xsd
index 7a5defefbd..5863d5d560 100644
--- a/dspace/config/controlled-vocabularies/controlledvocabulary.xsd
+++ b/dspace/config/controlled-vocabularies/controlledvocabulary.xsd
@@ -56,7 +56,7 @@ or refer to the Web site http://dspace-dev.dsi.uminho.pt.
 					</xs:complexType>
 				</xs:element>
 			</xs:all>
-			<xs:attribute name="id" type="xs:ID" use="optional"/>
+			<xs:attribute name="id" type="xs:ID" use="required"/>
 			<xs:attribute name="label" type="xs:string" use="required"/>
 			<xs:attribute name="selectable" type="xs:boolean" default="true"/>
 		</xs:complexType>