diff --git a/lib/constants.js b/lib/constants.js
index 4c9dfd2..a04bfd8 100644
--- a/lib/constants.js
+++ b/lib/constants.js
@@ -8,7 +8,7 @@ module.exports.NODE_TYPES = {
   ELEMENT_NODE: 1,
   ATTRIBUTE_NODE: 2, // historical
   TEXT_NODE: 3,
-  CDATA_SECTION_NODE: 4, // historical
+  CDATA_SECTION_NODE: 4,
   ENTITY_REFERENCE_NODE: 5, // historical
   ENTITY_NODE: 6, // historical
   PROCESSING_INSTRUCTION_NODE: 7,
diff --git a/lib/serialization.js b/lib/serialization.js
index dcef496..c8c5e13 100644
--- a/lib/serialization.js
+++ b/lib/serialization.js
@@ -303,6 +303,10 @@ function serializeElement(node, namespace, prefixMap, requireWellFormed, refs) {
   return markup;
 }
 
+function serializeCDATASection(node) {
+  return "<![CDATA[" + node.data + "]]>";
+}
+
 /**
  * @param {{prefixIndex: number}} refs
  */
@@ -352,6 +356,8 @@ function xmlSerialization(node, namespace, prefixMap, requireWellFormed, refs) {
       );
     case NODE_TYPES.ATTRIBUTE_NODE:
       return "";
+    case NODE_TYPES.CDATA_SECTION_NODE:
+      return serializeCDATASection(node);
     default:
       throw new TypeError("Only Nodes and Attr objects can be serialized");
   }
diff --git a/test/wpt/XMLSerializer-serializeToString.test.js b/test/wpt/XMLSerializer-serializeToString.test.js
index 5e5ef83..1515179 100644
--- a/test/wpt/XMLSerializer-serializeToString.test.js
+++ b/test/wpt/XMLSerializer-serializeToString.test.js
@@ -77,4 +77,13 @@ describe("WPT", () => {
       '<root><child1>value1</child1><html:br xmlns:html="http://www.w3.org/1999/xhtml" /></root>'
     );
   });
+
+  test("check CDATASection nodes are serialized correctly", () => {
+    const markup =
+      "<xhtml><style><![CDATA[ a > b { color: red; } ]]></style></xhtml>";
+
+    const document = new DOMParser().parseFromString(markup, "application/xml");
+
+    expect(new XMLSerializer().serializeToString(document)).toEqual(markup);
+  });
 });