diff --git a/Marlin/Configuration.h b/Marlin/Configuration.h
index 05277655c4..30d7427fc4 100644
--- a/Marlin/Configuration.h
+++ b/Marlin/Configuration.h
@@ -111,7 +111,6 @@
  * :[-2, -1, 0, 1, 2, 3, 4, 5, 6, 7]
  */
 #define SERIAL_PORT_2 1
-#define NUM_SERIAL 2
 
 /**
  * This setting determines the communication speed of the printer.