diff --git a/lib/nokogiri/xml/document_fragment.rb b/lib/nokogiri/xml/document_fragment.rb
index 7cf03773c9..af4450c082 100644
--- a/lib/nokogiri/xml/document_fragment.rb
+++ b/lib/nokogiri/xml/document_fragment.rb
@@ -51,7 +51,11 @@ def to_xml *args
       ###
       # Search this fragment.  See Nokogiri::XML::Node#css
       def css *args
-        children.css(*args)
+        if children.any?
+          children.css(*args)
+        else
+          NodeSet.new(document)
+        end
       end
 
       alias :serialize :to_s
diff --git a/lib/nokogiri/xml/fragment_handler.rb b/lib/nokogiri/xml/fragment_handler.rb
index 68e046c14d..06f63e645b 100644
--- a/lib/nokogiri/xml/fragment_handler.rb
+++ b/lib/nokogiri/xml/fragment_handler.rb
@@ -28,13 +28,15 @@ def start_element name, attrs = []
         @doc_started = true if @original_html =~ regex
         return unless @doc_started
 
-        if @document.root and match = name.match(QNAME_REGEX)
-          prefix, name = match[1], match[2]
-          ns = @document.root.namespace_definitions.detect { |x|
-            x.prefix == prefix
-          }
-        else
-          ns = nil
+        ns = nil
+        if @document.root
+          match = name.match(QNAME_REGEX)
+          if match
+            prefix, name = match[1], match[2]
+            ns = @document.root.namespace_definitions.detect { |x|
+              x.prefix == prefix
+            }
+          end
         end
 
         node = Element.new(name, @document)
diff --git a/test/html/test_document_fragment.rb b/test/html/test_document_fragment.rb
index e6f66ba40b..55a249999f 100644
--- a/test/html/test_document_fragment.rb
+++ b/test/html/test_document_fragment.rb
@@ -39,6 +39,16 @@ def test_fragment_should_have_document
         assert_equal @html, fragment.document
       end
 
+      def test_empty_fragment_should_be_searchable_by_css
+        fragment = Nokogiri::HTML.fragment("")
+        assert_equal 0, fragment.css("a").size
+      end
+
+      def test_empty_fragment_should_be_searchable
+        fragment = Nokogiri::HTML.fragment("")
+        assert_equal 0, fragment.search("//a").size
+      end
+
       def test_name
         fragment = Nokogiri::HTML::DocumentFragment.new(@html)
         assert_equal '#document-fragment', fragment.name