diff --git a/UPGRADE-4.1.md b/UPGRADE-4.1.md
index d76e3a3796188..e197d7bcc0066 100644
--- a/UPGRADE-4.1.md
+++ b/UPGRADE-4.1.md
@@ -74,6 +74,11 @@ SecurityBundle
  * The `SecurityUserValueResolver` class is deprecated, use
    `Symfony\Component\Security\Http\Controller\UserValueResolver` instead.
 
+Serializer
+----------
+
+ * Decoding XML with `XmlEncoder` now ignores comment node types by default.
+
 Translation
 -----------
 
diff --git a/src/Symfony/Component/Serializer/CHANGELOG.md b/src/Symfony/Component/Serializer/CHANGELOG.md
index a4e8bf499f5c6..d45e771e610b8 100644
--- a/src/Symfony/Component/Serializer/CHANGELOG.md
+++ b/src/Symfony/Component/Serializer/CHANGELOG.md
@@ -11,6 +11,8 @@ CHANGELOG
 * added optional `bool $escapeFormulas = false` argument to `CsvEncoder::__construct`
 * added `AbstractObjectNormalizer::setMaxDepthHandler` to set a handler to call when the configured
   maximum depth is reached
+* added optional `int[] $ignoredNodeTypes` argument to `XmlEncoder::__construct`. XML decoding now
+  ignores comment node types by default.
 
 4.0.0
 -----
diff --git a/src/Symfony/Component/Serializer/Encoder/XmlEncoder.php b/src/Symfony/Component/Serializer/Encoder/XmlEncoder.php
index fec0fefd08ec0..0a6cc0edbdcc2 100644
--- a/src/Symfony/Component/Serializer/Encoder/XmlEncoder.php
+++ b/src/Symfony/Component/Serializer/Encoder/XmlEncoder.php
@@ -37,16 +37,19 @@ class XmlEncoder implements EncoderInterface, DecoderInterface, NormalizationAwa
     private $context;
     private $rootNodeName = 'response';
     private $loadOptions;
+    private $ignoredNodeTypes;
 
     /**
      * Construct new XmlEncoder and allow to change the root node element name.
      *
-     * @param int|null $loadOptions A bit field of LIBXML_* constants
+     * @param int|null $loadOptions      A bit field of LIBXML_* constants
+     * @param int[]    $ignoredNodeTypes an array of ignored XML node types, each one of the DOM Predefined XML_* Constants
      */
-    public function __construct(string $rootNodeName = 'response', int $loadOptions = null)
+    public function __construct(string $rootNodeName = 'response', int $loadOptions = null, array $ignoredNodeTypes = array(XML_PI_NODE, XML_COMMENT_NODE))
     {
         $this->rootNodeName = $rootNodeName;
         $this->loadOptions = null !== $loadOptions ? $loadOptions : LIBXML_NONET | LIBXML_NOBLANKS;
+        $this->ignoredNodeTypes = $ignoredNodeTypes;
     }
 
     /**
@@ -105,7 +108,7 @@ public function decode($data, $format, array $context = array())
             if (XML_DOCUMENT_TYPE_NODE === $child->nodeType) {
                 throw new NotEncodableValueException('Document types are not allowed.');
             }
-            if (!$rootNode && XML_PI_NODE !== $child->nodeType) {
+            if (!$rootNode && !\in_array($child->nodeType, $this->ignoredNodeTypes, true)) {
                 $rootNode = $child;
             }
         }
@@ -316,7 +319,7 @@ private function parseXmlValue(\DOMNode $node, array $context = array())
         $value = array();
 
         foreach ($node->childNodes as $subnode) {
-            if (XML_PI_NODE === $subnode->nodeType) {
+            if (\in_array($subnode->nodeType, $this->ignoredNodeTypes, true)) {
                 continue;
             }
 
diff --git a/src/Symfony/Component/Serializer/Tests/Encoder/XmlEncoderTest.php b/src/Symfony/Component/Serializer/Tests/Encoder/XmlEncoderTest.php
index 17f7b93b4d837..39bb557c3c6c0 100644
--- a/src/Symfony/Component/Serializer/Tests/Encoder/XmlEncoderTest.php
+++ b/src/Symfony/Component/Serializer/Tests/Encoder/XmlEncoderTest.php
@@ -515,6 +515,62 @@ public function testDecodeIgnoreWhiteSpace()
         $this->assertEquals($expected, $this->encoder->decode($source, 'xml'));
     }
 
+    public function testDecodeIgnoreComments()
+    {
+        $source = <<<'XML'
+<?xml version="1.0"?>
+<!-- This comment should not become the root node. -->
+<people>
+    <person>
+        <!-- Even if the first comment didn't become the root node, we don't
+             want this comment either. -->
+        <firstname>Benjamin</firstname>
+        <lastname>Alexandre</lastname>
+    </person>
+    <person>
+        <firstname>Damien</firstname>
+        <lastname>Clay</lastname>
+    </person>
+</people>
+XML;
+
+        $expected = array('person' => array(
+          array('firstname' => 'Benjamin', 'lastname' => 'Alexandre'),
+          array('firstname' => 'Damien', 'lastname' => 'Clay'),
+        ));
+
+        $this->assertEquals($expected, $this->encoder->decode($source, 'xml'));
+    }
+
+    public function testDecodePreserveComments()
+    {
+        $source = <<<'XML'
+<?xml version="1.0"?>
+<people>
+    <person>
+        <!-- This comment should be decoded. -->
+        <firstname>Benjamin</firstname>
+        <lastname>Alexandre</lastname>
+    </person>
+    <person>
+        <firstname>Damien</firstname>
+        <lastname>Clay</lastname>
+    </person>
+</people>
+XML;
+
+        $this->encoder = new XmlEncoder('people', null, array(XML_PI_NODE));
+        $serializer = new Serializer(array(new CustomNormalizer()), array('xml' => new XmlEncoder()));
+        $this->encoder->setSerializer($serializer);
+
+        $expected = array('person' => array(
+          array('firstname' => 'Benjamin', 'lastname' => 'Alexandre', '#comment' => ' This comment should be decoded. '),
+          array('firstname' => 'Damien', 'lastname' => 'Clay'),
+        ));
+
+        $this->assertEquals($expected, $this->encoder->decode($source, 'xml'));
+    }
+
     public function testDecodeAlwaysAsCollection()
     {
         $this->encoder = new XmlEncoder('response', null);