diff --git a/lib/hawat/app.py b/lib/hawat/app.py
index fb15e377fda13651cc2b2bb7b9470ab613623d45..40505158ce571c95ca9f7dee974c776c61b1ff68 100644
--- a/lib/hawat/app.py
+++ b/lib/hawat/app.py
@@ -190,6 +190,14 @@ def _setup_app_core(app):
     @app.errorhandler(400)
     def eh_badrequest(err):  # pylint: disable=locally-disabled,unused-variable
         """Flask error handler to be called to service HTTP 400 error."""
+        flask.current_app.logger.critical(
+            "Bad Request Error:\n%s",
+            ''.join(
+                traceback.TracebackException(
+                    *sys.exc_info()
+                ).format()
+            )
+        )
         return hawat.errors.error_handler_switch(400, err)
 
     @app.errorhandler(403)