diff --git a/paramiko/pkey.py b/paramiko/pkey.py
index f494c80e8..9f9cc5436 100644
--- a/paramiko/pkey.py
+++ b/paramiko/pkey.py
@@ -324,7 +324,9 @@ def _read_private_key_file(self, tag, filename, password=None):
 
     def _read_private_key(self, tag, f, password=None):
         lines = f.readlines()
-
+        if not lines:
+            raise SSHException("no lines in {} private key file".format(tag))
+            
         # find the BEGIN tag
         start = 0
         m = self.BEGIN_TAG.match(lines[start])