diff --git a/spring-integration-core/src/main/java/org/springframework/integration/config/spring-integration-core-1.0.xsd b/spring-integration-core/src/main/java/org/springframework/integration/config/spring-integration-core-1.0.xsd
index f6d957138b..78b35e17fc 100644
--- a/spring-integration-core/src/main/java/org/springframework/integration/config/spring-integration-core-1.0.xsd
+++ b/spring-integration-core/src/main/java/org/springframework/integration/config/spring-integration-core-1.0.xsd
@@ -133,7 +133,7 @@
 			<xsd:complexContent>
 				<xsd:extension base="beans:identifiedType">
 					<xsd:sequence>
-						<xsd:element ref="schedule" minOccurs="0" maxOccurs="1"/>
+						<xsd:element ref="schedule" minOccurs="1" maxOccurs="1"/>
 					</xsd:sequence>
 					<xsd:attribute name="source" type="xsd:string" use="required"/>
 					<xsd:attribute name="channel" type="xsd:string" use="required"/>