diff --git a/tornado/ioloop.py b/tornado/ioloop.py
index 730d9ba..fe465eb 100644
--- a/tornado/ioloop.py
+++ b/tornado/ioloop.py
@@ -212,7 +212,7 @@
         try:
             self._impl.unregister(fd)
         except (OSError, IOError):
-            logging.debug("Error deleting fd from IOLoop", exc_info=True)
+            logging.error("Error deleting fd from IOLoop", exc_info=True)
 
     def set_blocking_signal_threshold(self, seconds, action):
         """Sends a signal if the ioloop is blocked for more than s seconds.