diff -u b/core/lib/Drupal/Core/Config/DatabaseStorage.php b/core/lib/Drupal/Core/Config/DatabaseStorage.php
--- b/core/lib/Drupal/Core/Config/DatabaseStorage.php
+++ b/core/lib/Drupal/Core/Config/DatabaseStorage.php
@@ -68,7 +68,8 @@
    */
   public function exists($name) {
     try {
-      return (bool) $this->connection->queryRange('SELECT 1 FROM {' . $this->connection->escapeTable($this->table) . '} WHERE name = :name', 0, 1, array(
+      return (bool) $this->connection->queryRange('SELECT 1 FROM {' . $this->connection->escapeTable($this->table) . '} WHERE collection = :collection AND name = :name', 0, 1, array(
+        ':collection' => $this->collection,
         ':name' => $name,
       ), $this->options)->fetchField();
     }
diff -u b/core/modules/config/lib/Drupal/config/Tests/Storage/ConfigStorageTestBase.php b/core/modules/config/lib/Drupal/config/Tests/Storage/ConfigStorageTestBase.php
--- b/core/modules/config/lib/Drupal/config/Tests/Storage/ConfigStorageTestBase.php
+++ b/core/modules/config/lib/Drupal/config/Tests/Storage/ConfigStorageTestBase.php
@@ -193,11 +193,13 @@
 
     // Create configuration in a new collection.
     $new_storage = $this->storage->createCollection('collection.sub.new');
+    $this->assertFalse($new_storage->exists($name));
     $this->assertEqual(array(), $new_storage->listAll());
     $new_storage->write($name, $data);
     $this->assertIdentical($result, TRUE);
     $this->assertIdentical($data, $new_storage->read($name));
     $this->assertEqual(array($name), $new_storage->listAll());
+    $this->assertTrue($new_storage->exists($name));
     $new_data = array('foo' => 'baz');
     $new_storage->write($name, $new_data);
     $this->assertIdentical($result, TRUE);
@@ -205,11 +207,13 @@
 
     // Create configuration in another collection.
     $another_storage = $this->storage->createCollection('collection.sub.another');
+    $this->assertFalse($another_storage->exists($name));
     $this->assertEqual(array(), $another_storage->listAll());
     $another_storage->write($name, $new_data);
     $this->assertIdentical($result, TRUE);
     $this->assertIdentical($new_data, $another_storage->read($name));
     $this->assertEqual(array($name), $another_storage->listAll());
+    $this->assertTrue($another_storage->exists($name));
 
     // Create configuration in yet another collection.
     $alt_storage = $this->storage->createCollection('alternate');