diff --git a/Lib/ftplib.py b/Lib/ftplib.py
index 6aecd28..8d99158 100644
--- a/Lib/ftplib.py
+++ b/Lib/ftplib.py
@@ -39,6 +39,7 @@
 import os
 import sys
 import socket
+import warnings
 from socket import _GLOBAL_DEFAULT_TIMEOUT
 
 __all__ = ["FTP","Netrc"]
@@ -953,6 +954,8 @@
     __defacct = None
 
     def __init__(self, filename=None):
+        warnings.warn("This class is deprecated, use the netrc module instead",
+                      DeprecationWarning, 2)
         if filename is None:
             if "HOME" in os.environ:
                 filename = os.path.join(os.environ["HOME"],
diff --git a/Lib/test/test_ftplib.py b/Lib/test/test_ftplib.py
index 4dfc457..2e89973 100644
--- a/Lib/test/test_ftplib.py
+++ b/Lib/test/test_ftplib.py
@@ -985,8 +985,19 @@
         ftp.close()
 
 
+class TestNetrcDeprecation(TestCase):
+
+    def test_deprecation(self):
+        with support.temp_cwd(), support.EnvironmentVarGuard() as env:
+            env['HOME'] = os.getcwd()
+            open('.netrc', 'w').close()
+            with self.assertWarns(DeprecationWarning):
+                ftplib.Netrc()
+
+
+
 def test_main():
-    tests = [TestFTPClass, TestTimeouts]
+    tests = [TestFTPClass, TestTimeouts, TestNetrcDeprecation]
     if support.IPV6_ENABLED:
         tests.append(TestIPv6Environment)
 
diff --git a/Misc/NEWS b/Misc/NEWS
index d702ed1..ac29b18 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -260,6 +260,9 @@
 Library
 -------
 
+- Issue #6623: Added explicit DeprecationWarning for ftplib.netrc, which has
+  been deprecated and undocumented for a long time.
+
 - Issue #13700: Fix byte/string handling in imaplib authentication when an
   authobject is specified.