diff --git a/Lib/StringIO.py b/Lib/StringIO.py
index 9225c052864..38b3e368353 100644
--- a/Lib/StringIO.py
+++ b/Lib/StringIO.py
@@ -39,7 +39,7 @@ __all__ = ["StringIO"]
 class StringIO:
     def __init__(self, buf = ''):
         # Force self.buf to be a string or unicode
-        if not isinstance(buf, types.UnicodeType):
+        if not isinstance(buf, types.StringTypes):
             buf = str(buf)
         self.buf = buf
         self.len = len(buf)
@@ -138,7 +138,7 @@ class StringIO:
             raise ValueError, "I/O operation on closed file"
         if not s: return
         # Force s to be a string or unicode
-        if not isinstance(s, types.UnicodeType):
+        if not isinstance(s, types.StringTypes):
             s = str(s)
         if self.pos > self.len:
             self.buflist.append('\0'*(self.pos - self.len))
diff --git a/Lib/test/test_StringIO.py b/Lib/test/test_StringIO.py
index a340e3b6aee..9deba0d85a3 100644
--- a/Lib/test/test_StringIO.py
+++ b/Lib/test/test_StringIO.py
@@ -73,6 +73,8 @@ class TestStringIO(TestGenericStringIO):
 
     def test_unicode(self):
 
+        if not test_support.have_unicode: return
+
         # The StringIO module also supports concatenating Unicode
         # snippets to larger Unicode strings. This is tested by this
         # method. Note that cStringIO does not support this extension.