diff --git a/constants.asm b/constants.asm
index 19049702e..75d902496 100644
--- a/constants.asm
+++ b/constants.asm
@@ -283,6 +283,9 @@ SCREEN_HEIGHT EQU 18
 SCREEN_WIDTH_PX EQU 160
 SCREEN_HEIGHT_PX EQU 144
 
+BG_MAP_WIDTH  EQU 32
+BG_MAP_HEIGHT EQU 32
+
 TILE_WIDTH EQU 8