diff --git a/erpnext/stock/report/stock_ageing/stock_ageing.py b/erpnext/stock/report/stock_ageing/stock_ageing.py
index 0f37b3f0116..4e9be3df364 100644
--- a/erpnext/stock/report/stock_ageing/stock_ageing.py
+++ b/erpnext/stock/report/stock_ageing/stock_ageing.py
@@ -275,6 +275,7 @@ class FIFOSlots:
 					else:
 						serial_nos = get_serial_nos_from_bundle(d.serial_and_batch_bundle) or []
 
+				serial_nos = self.uppercase_serial_nos(serial_nos)
 				if d.actual_qty > 0:
 					self.__compute_incoming_stock(d, fifo_queue, transferred_item_key, serial_nos)
 				else:
@@ -291,6 +292,10 @@ class FIFOSlots:
 
 		return self.item_details
 
+	def uppercase_serial_nos(self, serial_nos):
+		"Convert serial nos to uppercase for uniformity."
+		return [sn.upper() for sn in serial_nos]
+
 	def __init_key_stores(self, row: dict) -> tuple:
 		"Initialise keys and FIFO Queue."