diff --git a/core/src/main/java/org/elasticsearch/cluster/metadata/MetaData.java b/core/src/main/java/org/elasticsearch/cluster/metadata/MetaData.java
index 9945de1f8d3..d4e7baac790 100644
--- a/core/src/main/java/org/elasticsearch/cluster/metadata/MetaData.java
+++ b/core/src/main/java/org/elasticsearch/cluster/metadata/MetaData.java
@@ -41,6 +41,7 @@ import org.elasticsearch.common.collect.ImmutableOpenMap;
 import org.elasticsearch.common.io.stream.StreamInput;
 import org.elasticsearch.common.io.stream.StreamOutput;
 import org.elasticsearch.common.logging.ESLogger;
+import org.elasticsearch.common.logging.support.LoggerMessageFormat;
 import org.elasticsearch.common.regex.Regex;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.settings.loader.SettingsLoader;
@@ -1029,12 +1030,18 @@ public class MetaData implements Iterable<IndexMetaData>, Diffable<MetaData>, Fr
 
                 for (ObjectObjectCursor<String, AliasMetaData> aliasCursor : indexMetaData.getAliases()) {
                     AliasMetaData aliasMetaData = aliasCursor.value;
-                    AliasOrIndex.Alias aliasOrIndex = (AliasOrIndex.Alias) aliasAndIndexLookup.get(aliasMetaData.getAlias());
+                    AliasOrIndex aliasOrIndex = aliasAndIndexLookup.get(aliasMetaData.getAlias());
                     if (aliasOrIndex == null) {
                         aliasOrIndex = new AliasOrIndex.Alias(aliasMetaData, indexMetaData);
                         aliasAndIndexLookup.put(aliasMetaData.getAlias(), aliasOrIndex);
+                    } else if (aliasOrIndex instanceof AliasOrIndex.Alias) {
+                        AliasOrIndex.Alias alias = (AliasOrIndex.Alias) aliasOrIndex;
+                        alias.addIndex(indexMetaData);
+                    } else if (aliasOrIndex instanceof AliasOrIndex.Index) {
+                        AliasOrIndex.Index index = (AliasOrIndex.Index) aliasOrIndex;
+                        throw new IllegalStateException("index and alias names need to be unique, but alias [" + aliasMetaData.getAlias() + "] and index [" + index.getIndex().getIndex() + "] have the same name");
                     } else {
-                        aliasOrIndex.addIndex(indexMetaData);
+                        throw new IllegalStateException("unexpected alias [" + aliasMetaData.getAlias() + "][" + aliasOrIndex + "]");
                     }
                 }
             }
diff --git a/core/src/test/java/org/elasticsearch/cluster/metadata/MetaDataTests.java b/core/src/test/java/org/elasticsearch/cluster/metadata/MetaDataTests.java
new file mode 100644
index 00000000000..59116859322
--- /dev/null
+++ b/core/src/test/java/org/elasticsearch/cluster/metadata/MetaDataTests.java
@@ -0,0 +1,44 @@
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.elasticsearch.cluster.metadata;
+
+import org.elasticsearch.Version;
+import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.test.ESTestCase;
+
+import static org.hamcrest.Matchers.equalTo;
+
+public class MetaDataTests extends ESTestCase {
+
+    public void testIndexAndAliasWithSameName() {
+        IndexMetaData.Builder builder = IndexMetaData.builder("index")
+                .settings(Settings.builder().put(IndexMetaData.SETTING_VERSION_CREATED, Version.CURRENT))
+                .numberOfShards(1)
+                .numberOfReplicas(0)
+                .putAlias(AliasMetaData.builder("index").build());
+        try {
+            MetaData.builder().put(builder).build();
+            fail("expection should have been thrown");
+        } catch (IllegalStateException e) {
+            assertThat(e.getMessage(), equalTo("index and alias names need to be unique, but alias [index] and index [index] have the same name"));
+        }
+    }
+
+}