diff --git a/papermill/execute.py b/papermill/execute.py
index <HASH>..<HASH> 100644
--- a/papermill/execute.py
+++ b/papermill/execute.py
@@ -180,6 +180,7 @@ def parameterize_notebook(nb, parameters, report_mode=False):
         after = nb.cells[param_cell_index + 1 :]
     else:
         # Inject to the top of the notebook
+        logger.warning("Input notebook does not contain a cell with tag 'parameters'")
         before = []
         after = nb.cells
Log a warning if the input notebook doesn't have
a parameters cell