diff --git a/maven-project/src/main/java/org/apache/maven/project/DefaultMavenProjectBuilder.java b/maven-project/src/main/java/org/apache/maven/project/DefaultMavenProjectBuilder.java
index 1523e969ae..a2ad5223e5 100644
--- a/maven-project/src/main/java/org/apache/maven/project/DefaultMavenProjectBuilder.java
+++ b/maven-project/src/main/java/org/apache/maven/project/DefaultMavenProjectBuilder.java
@@ -290,7 +290,14 @@ public class DefaultMavenProjectBuilder
         // Always cache files in the source tree over those in the repository
         MavenProject p = new MavenProject( model );
         p.setFile( projectDescriptor );
-        modelCache.put( createCacheKey( model.getGroupId(), model.getArtifactId(), model.getVersion() ), p );
+        
+        String modelKey = createCacheKey( model.getGroupId(), model.getArtifactId(), model.getVersion() );
+        if ( modelCache.containsKey( modelKey ) )
+        {
+            throw new ProjectBuildingException( model.getGroupId() + ":" + model.getArtifactId(), 
+                    "Duplicate project ID found in " + projectDescriptor.getAbsolutePath() );
+        }
+        modelCache.put( modelKey, p );
 
         MavenProject project = build( projectDescriptor.getAbsolutePath(), model, localRepository,
                                       buildArtifactRepositories( getSuperModel() ),
@@ -852,6 +859,12 @@ public class DefaultMavenProjectBuilder
             {
                 throw new ProjectBuildingException( projectId, "Missing artifactId element from parent element" );
             }
+            else if ( parentModel.getGroupId().equals( model.getGroupId() ) &&  
+                    parentModel.getArtifactId().equals( model.getArtifactId() ) )
+            {
+                throw new ProjectBuildingException( projectId, "Parent element is a duplicate of " +
+                        "the current project " );
+            }
             else if ( StringUtils.isEmpty( parentModel.getVersion() ) )
             {
                 throw new ProjectBuildingException( projectId, "Missing version element from parent element" );
diff --git a/maven-project/src/main/java/org/apache/maven/project/validation/DefaultModelValidator.java b/maven-project/src/main/java/org/apache/maven/project/validation/DefaultModelValidator.java
index 34e38b70aa..df1e04ec4d 100644
--- a/maven-project/src/main/java/org/apache/maven/project/validation/DefaultModelValidator.java
+++ b/maven-project/src/main/java/org/apache/maven/project/validation/DefaultModelValidator.java
@@ -21,6 +21,7 @@ import org.apache.maven.model.Build;
 import org.apache.maven.model.Dependency;
 import org.apache.maven.model.DependencyManagement;
 import org.apache.maven.model.Model;
+import org.apache.maven.model.Parent;
 import org.apache.maven.model.Plugin;
 import org.apache.maven.model.ReportPlugin;
 import org.apache.maven.model.Reporting;
@@ -60,6 +61,16 @@ public class DefaultModelValidator
             result.addMessage( "Packaging '" + model.getPackaging() + "' is invalid. Aggregator projects " +
                     "require 'pom' as packaging." );
         }
+        
+        Parent parent = model.getParent();
+        if ( parent != null )
+        {
+            if ( parent.getGroupId().equals( model.getGroupId() ) && 
+                    parent.getArtifactId().equals( model.getArtifactId() ) )
+            {
+                result.addMessage( "The parent element cannot have the same ID as the project." );
+            }
+        }
 
         validateStringNotEmpty( "version", result, model.getVersion() );