diff --git a/src/Symfony/Component/DependencyInjection/ParameterBag/EnvPlaceholderParameterBag.php b/src/Symfony/Component/DependencyInjection/ParameterBag/EnvPlaceholderParameterBag.php
index 907acd9679..c0bfa33af4 100644
--- a/src/Symfony/Component/DependencyInjection/ParameterBag/EnvPlaceholderParameterBag.php
+++ b/src/Symfony/Component/DependencyInjection/ParameterBag/EnvPlaceholderParameterBag.php
@@ -30,7 +30,9 @@ class EnvPlaceholderParameterBag extends ParameterBag
             $env = substr($name, 4, -1);
 
             if (isset($this->envPlaceholders[$env])) {
-                return $this->envPlaceholders[$env][0];
+                foreach ($this->envPlaceholders[$env] as $placeholder) {
+                    return $placeholder; // return first result
+                }
             }
             if (preg_match('/\W/', $env)) {
                 throw new InvalidArgumentException(sprintf('Invalid %s name: only "word" characters are allowed.', $name));
@@ -44,7 +46,11 @@ class EnvPlaceholderParameterBag extends ParameterBag
                 }
             }
 
-            return $this->envPlaceholders[$env][] = sprintf('env_%s_%s', $env, md5($name.uniqid(mt_rand(), true)));
+            $uniqueName = md5($name.uniqid(mt_rand(), true));
+            $placeholder = sprintf('env_%s_%s', $env, $uniqueName);
+            $this->envPlaceholders[$env][$placeholder] = $placeholder;
+
+            return $placeholder;
         }
 
         return parent::get($name);
diff --git a/src/Symfony/Component/DependencyInjection/Tests/ParameterBag/EnvPlaceholderParameterBagTest.php b/src/Symfony/Component/DependencyInjection/Tests/ParameterBag/EnvPlaceholderParameterBagTest.php
index 4412118b90..2a85bbf999 100644
--- a/src/Symfony/Component/DependencyInjection/Tests/ParameterBag/EnvPlaceholderParameterBagTest.php
+++ b/src/Symfony/Component/DependencyInjection/Tests/ParameterBag/EnvPlaceholderParameterBagTest.php
@@ -23,4 +23,19 @@ class EnvPlaceholderParameterBagTest extends \PHPUnit_Framework_TestCase
         $bag = new EnvPlaceholderParameterBag();
         $bag->get('env(%foo%)');
     }
+
+    public function testMergeWillNotDuplicateIdenticalParameters()
+    {
+        $originalPlaceholders = array('database_host' => array('localhost'));
+        $firstBag = new EnvPlaceholderParameterBag($originalPlaceholders);
+
+        // initialize placeholders
+        $firstBag->get('env(database_host)');
+        $secondBag = clone $firstBag;
+
+        $firstBag->mergeEnvPlaceholders($secondBag);
+        $mergedPlaceholders = $firstBag->getEnvPlaceholders();
+
+        $this->assertCount(1, $mergedPlaceholders['database_host']);
+    }
 }