diff --git a/translate/storage/dtd.py b/translate/storage/dtd.py
index feba993d80..3d303938a6 100644
--- a/translate/storage/dtd.py
+++ b/translate/storage/dtd.py
@@ -57,6 +57,8 @@
 
 
 def quotefordtd(source):
+    if '%' in source:
+        source = source.replace("%", "")
     if '"' in source:
         if "'" in source:
             return "'" + source.replace("'", ''') + "'"
@@ -75,6 +77,7 @@ def unquotefromdtd(source):
     extracted, quotefinished = quote.extractwithoutquotes(source, quotechar, quotechar, allowreentry=False)
     if quotechar == "'" and "'" in extracted:
         extracted = extracted.replace("'", "'")
+    extracted = extracted.replace("", "%")
     # the quote characters should be the first and last characters in the string
     # of course there could also be quote characters within the string; not handled here
     return extracted
diff --git a/translate/storage/test_dtd.py b/translate/storage/test_dtd.py
index f60bda1e7f..7f878519e8 100644
--- a/translate/storage/test_dtd.py
+++ b/translate/storage/test_dtd.py
@@ -24,6 +24,15 @@ def test_roundtrip_quoting():
         assert special == unquoted_special
 
 
+def test_quotefordtd():
+    """Test quoting and unqouting dtd definitions"""
+    def tester(raw_original, dtd_ready_result):
+        #print dtd.quotefordtd(raw_original)
+        assert dtd.quotefordtd(raw_original) == dtd_ready_result
+        #print dtd.unquotefromdtd(dtd_ready_result)
+        assert dtd.unquotefromdtd(dtd_ready_result) == raw_original
+    tester("Unintentional variable %S", '"Unintentional variable S"')
+
 def test_removeinvalidamp(recwarn):
     """tests the the removeinvalidamps function"""