diff --git a/src/AliasStorageHelper.php b/src/AliasStorageHelper.php
index 06ce2c4..0c6e9e8 100644
--- a/src/AliasStorageHelper.php
+++ b/src/AliasStorageHelper.php
@@ -114,6 +114,11 @@ class AliasStorageHelper implements AliasStorageHelperInterface {
       return NULL;
     }
 
+    // Don't create a new alias if it is identical to the current alias.
+    if ($existing_alias && $existing_alias->getAlias() == $alias) {
+      return NULL;
+    }
+
     // Update the existing alias if there is one and the configuration is set to
     // replace it.
     if ($existing_alias && $config->get('update_action') == PathautoGeneratorInterface::UPDATE_ACTION_DELETE) {
diff --git a/tests/src/Functional/PathautoTestHelperTrait.php b/tests/src/Functional/PathautoTestHelperTrait.php
index 6473c85..dd7694d 100644
--- a/tests/src/Functional/PathautoTestHelperTrait.php
+++ b/tests/src/Functional/PathautoTestHelperTrait.php
@@ -134,6 +134,17 @@ trait PathautoTestHelperTrait {
     $this->assertEmpty($alias, t('Alias with conditions @conditions not found.', ['@conditions' => var_export($conditions, TRUE)]));
   }
 
+  public function assertAliasIsUnique($conditions) {
+    $storage = \Drupal::entityTypeManager()->getStorage('path_alias');
+    $query = $storage->getQuery()->accessCheck(FALSE);
+    foreach ($conditions as $field => $value) {
+      $query->condition($field, $value);
+    }
+    $entities = $storage->loadMultiple($query->execute());
+
+    return $this->assertCount(1, $entities);
+  }
+
   public function deleteAllAliases() {
     \Drupal::service('pathauto.alias_storage_helper')->deleteAll();
     \Drupal::service('path_alias.manager')->cacheClear();
diff --git a/tests/src/Kernel/PathautoKernelTest.php b/tests/src/Kernel/PathautoKernelTest.php
index dd70405..853ace1 100644
--- a/tests/src/Kernel/PathautoKernelTest.php
+++ b/tests/src/Kernel/PathautoKernelTest.php
@@ -304,6 +304,11 @@ class PathautoKernelTest extends KernelTestBase {
     $this->assertEntityAlias($node, '/content/third-title');
     $this->assertAliasExists(['path' => '/' . $node->toUrl()->getInternalPath(), 'alias' => '/content/second-title']);
 
+    // Confirm that aliases are not duplicated when entities are re-saved.
+    $node->save();
+    $this->assertEntityAlias($node, '/content/third-title');
+    $this->assertAliasIsUnique(['path' => '/' . $node->toUrl()->getInternalPath(), 'alias' => '/content/third-title']);
+
     $config->set('update_action', PathautoGeneratorInterface::UPDATE_ACTION_DELETE);
     $config->save();
     $node->setTitle('Fourth title');