diff --git a/components/script/dom/domimplementation.rs b/components/script/dom/domimplementation.rs
index 37b75688c2b..8c0f9bd61ee 100644
--- a/components/script/dom/domimplementation.rs
+++ b/components/script/dom/domimplementation.rs
@@ -12,7 +12,7 @@ use dom::bindings::global::GlobalRef;
 use dom::bindings::inheritance::Castable;
 use dom::bindings::js::{JS, Root};
 use dom::bindings::reflector::{Reflector, reflect_dom_object};
-use dom::bindings::xmlname::validate_qualified_name;
+use dom::bindings::xmlname::{validate_qualified_name, namespace_from_domstring};
 use dom::document::DocumentSource;
 use dom::document::{Document, IsHTMLDocument};
 use dom::documenttype::DocumentType;
@@ -62,19 +62,26 @@ impl DOMImplementationMethods for DOMImplementation {
 
     // https://dom.spec.whatwg.org/#dom-domimplementation-createdocument
     fn CreateDocument(&self,
-                      namespace: Option<DOMString>,
+                      maybe_namespace: Option<DOMString>,
                       qname: DOMString,
                       maybe_doctype: Option<&DocumentType>)
                       -> Fallible<Root<XMLDocument>> {
         let win = self.document.window();
         let loader = DocumentLoader::new(&self.document.loader());
+        let namespace = namespace_from_domstring(maybe_namespace.to_owned());
+
+        let content_type = match namespace {
+            ns!(html) => "application/xhtml+xml",
+            ns!(svg) => "image/svg+xml",
+            _ => "application/xml"
+        };
 
         // Step 1.
         let doc = XMLDocument::new(win,
                                    None,
                                    None,
                                    IsHTMLDocument::NonHTMLDocument,
-                                   None,
+                                   Some(DOMString::from(content_type)),
                                    None,
                                    DocumentSource::NotFromParser,
                                    loader);
@@ -82,7 +89,7 @@ impl DOMImplementationMethods for DOMImplementation {
         let maybe_elem = if qname.is_empty() {
             None
         } else {
-            match doc.upcast::<Document>().CreateElementNS(namespace, qname) {
+            match doc.upcast::<Document>().CreateElementNS(maybe_namespace, qname) {
                 Err(error) => return Err(error),
                 Ok(elem) => Some(elem),
             }
diff --git a/tests/wpt/metadata/dom/nodes/DOMImplementation-createDocument.html.ini b/tests/wpt/metadata/dom/nodes/DOMImplementation-createDocument.html.ini
deleted file mode 100644
index 6ee786f53be..00000000000
--- a/tests/wpt/metadata/dom/nodes/DOMImplementation-createDocument.html.ini
+++ /dev/null
@@ -1,9 +0,0 @@
-[DOMImplementation-createDocument.html]
-  type: testharness
-  bug: https://github.com/servo/servo/issues/10743
-  [createDocument test 179: metadata for "http://www.w3.org/1999/xhtml","",null]
-    expected: FAIL
-
-  [createDocument test 180: metadata for "http://www.w3.org/2000/svg","",null]
-    expected: FAIL
-
diff --git a/tests/wpt/web-platform-tests/dom/nodes/DOMImplementation-createDocument.html b/tests/wpt/web-platform-tests/dom/nodes/DOMImplementation-createDocument.html
index a982f23d861..d64bf3640d7 100644
--- a/tests/wpt/web-platform-tests/dom/nodes/DOMImplementation-createDocument.html
+++ b/tests/wpt/web-platform-tests/dom/nodes/DOMImplementation-createDocument.html
@@ -123,7 +123,7 @@ test(function() {
         var doc = document.implementation.createDocument(namespace, qualifiedName, doctype)
         assert_equals(doc.compatMode, "CSS1Compat")
         assert_equals(doc.characterSet, "UTF-8")
-        assert_equals(doc.contentType, namespace == htmlNamespace ? "text/html"
+        assert_equals(doc.contentType, namespace == htmlNamespace ? "application/xhtml+xml"
                                  : namespace == svgNamespace ?  "image/svg+xml"
                                  : "application/xml")
         assert_equals(doc.URL, "about:blank")
diff --git a/tests/wpt/web-platform-tests/dom/nodes/Document-contentType/contentType/createDocument.html b/tests/wpt/web-platform-tests/dom/nodes/Document-contentType/contentType/createDocument.html
index 1e4a22d712a..78a952de4a2 100644
--- a/tests/wpt/web-platform-tests/dom/nodes/Document-contentType/contentType/createDocument.html
+++ b/tests/wpt/web-platform-tests/dom/nodes/Document-contentType/contentType/createDocument.html
@@ -1,11 +1,11 @@
 <!DOCTYPE html>
-<title>document.implementation.createDocument: document.contentType === 'application/xml'</title>
+<title>document.implementation.createDocument: document.contentType === 'application/xhtml+xml'</title>
 <script src="/resources/testharness.js"></script>
 <script src="/resources/testharnessreport.js"></script>
 <div id=log></div>
 <script>
 test(function() {
   var doc = document.implementation.createDocument("http://www.w3.org/1999/xhtml", "html", null);
-  assert_equals(doc.contentType, "application/xml");
+  assert_equals(doc.contentType, "application/xhtml+xml");
 });
 </script>