diff --git a/src/am_map.cpp b/src/am_map.cpp
index 765443c20..dcfb361bf 100644
--- a/src/am_map.cpp
+++ b/src/am_map.cpp
@@ -1144,7 +1144,7 @@ static void AM_ScrollParchment (double dmapx, double dmapy)
 	mapystart = mapystart - dmapy * scale_mtof;
 
 	mapxstart = clamp(mapxstart, -40000., 40000.);
-	mapystart = clamp(mapxstart, -40000., 40000.);
+	mapystart = clamp(mapystart, -40000., 40000.);
 
 	if (mapback.isValid())
 	{