diff --git a/docs/changes.txt b/docs/changes.txt
index f9e3e0fa..80909407 100644
--- a/docs/changes.txt
+++ b/docs/changes.txt
@@ -49,6 +49,7 @@ Snes9x 1.56
   Football.
 - Attached APU instruction tracer and made some additions   (BearOso)
   to debugging output.
+- Fix line doubling in interlaced mode.                     (kps501)
 - Win32: Added dynamic rate control support for XAudio2     (OV2)
 - Win32: Added different volume level configuration for     (OV2)
   regular and turbo speed.
diff --git a/gfx.cpp b/gfx.cpp
index 2b87b3d9..46ec51a3 100644
--- a/gfx.cpp
+++ b/gfx.cpp
@@ -729,8 +729,8 @@ void S9xUpdateScreen (void)
 				GFX.PPL = GFX.RealPPL << 1;
 				GFX.DoInterlace = 2;
 
-				for (register int32 y = (int32) GFX.StartY - 1; y >= 0; y--)
-					memmove(GFX.Screen + y * GFX.PPL, GFX.Screen + y * GFX.RealPPL, IPPU.RenderedScreenWidth * sizeof(uint16));
+				for (register int32 y = (int32) GFX.StartY - 2; y >= 0; y--)
+					memmove(GFX.Screen + (y + 1) * GFX.PPL, GFX.Screen + y * GFX.RealPPL, GFX.PPL * sizeof(uint16));
 			}
 		}