diff --git a/Lib/encodings/utf_16.py b/Lib/encodings/utf_16.py
index 72be072..2c2638f 100644
--- a/Lib/encodings/utf_16.py
+++ b/Lib/encodings/utf_16.py
@@ -53,6 +53,9 @@
             self.bom_read = 1
         return codecs.StreamReader.read(self, size)
 
+    def readline(self, size=None):
+        raise NotImplementedError, '.readline() is not implemented for UTF-16'
+
 ### encodings module API
 
 def getregentry():
diff --git a/Lib/encodings/utf_16_be.py b/Lib/encodings/utf_16_be.py
index 2fd28da..63ac608 100644
--- a/Lib/encodings/utf_16_be.py
+++ b/Lib/encodings/utf_16_be.py
@@ -21,7 +21,9 @@
     pass
         
 class StreamReader(Codec,codecs.StreamReader):
-    pass
+
+    def readline(self, size=None):
+        raise NotImplementedError, '.readline() is not implemented for UTF-16-BE'
 
 ### encodings module API
 
diff --git a/Lib/encodings/utf_16_le.py b/Lib/encodings/utf_16_le.py
index fea9122..aa9d6f5 100644
--- a/Lib/encodings/utf_16_le.py
+++ b/Lib/encodings/utf_16_le.py
@@ -21,7 +21,9 @@
     pass
         
 class StreamReader(Codec,codecs.StreamReader):
-    pass
+
+    def readline(self, size=None):
+        raise NotImplementedError, '.readline() is not implemented for UTF-16-LE'
 
 ### encodings module API