diff --git a/Doc/library/random.rst b/Doc/library/random.rst
index b1df231..1bc9989 100644
--- a/Doc/library/random.rst
+++ b/Doc/library/random.rst
@@ -60,6 +60,13 @@
 uses the system function :func:`os.urandom` to generate random numbers
 from sources provided by the operating system.
 
+.. warning::
+
+   The pseudo-random generators of this module should not be used for
+   security purposes.  Use :func:`os.urandom` or :class:`SystemRandom` if
+   you require a cryptographically secure pseudo-random number generator.
+
+
 Bookkeeping functions: