diff --git a/src/mame/video/ygv608.cpp b/src/mame/video/ygv608.cpp
index 6a29eb1aea9..c6aa50353dc 100644
--- a/src/mame/video/ygv608.cpp
+++ b/src/mame/video/ygv608.cpp
@@ -1030,6 +1030,26 @@ inline void ygv608_device::draw_layer_roz(screen_device &screen, bitmap_ind16 &b
 		source_tilemap->draw(screen, bitmap, cliprect, 0, 0 );
 }
 
+void ygv608_device::ygv608_draw_mosaic(bitmap_ind16 &bitmap, const rectangle &cliprect, int n)
+{
+	int x, y, mask;
+
+	if (n <= 0)
+	{
+		return;
+	}
+
+	// mask to drop the lowest n-bits
+	mask = ~((1 << n) - 1);
+
+	for (y = cliprect.min_y; y <= cliprect.max_y; y++)
+	{
+		for (x = cliprect.min_x; x <= cliprect.max_x; x++)
+		{
+			bitmap.pix16(y, x) = bitmap.pix16(y & mask, x & mask);
+		}
+	}
+}
 
 uint32_t ygv608_device::update_screen(screen_device &screen, bitmap_ind16 &bitmap, const rectangle &cliprect)
 {
@@ -1175,6 +1195,8 @@ uint32_t ygv608_device::update_screen(screen_device &screen, bitmap_ind16 &bitma
 	else
 	{
 		draw_layer_roz(screen, m_work_bitmap, finalclip, m_tilemap_B);
+		if(m_mosaic_bplane > 0)
+			ygv608_draw_mosaic(m_work_bitmap, finalclip, m_mosaic_bplane);
 
 		if(m_planeB_trans_enable == true)
 			copybitmap_trans( bitmap, m_work_bitmap, 0, 0, 0, 0, finalclip, 0);
@@ -1192,6 +1214,8 @@ uint32_t ygv608_device::update_screen(screen_device &screen, bitmap_ind16 &bitma
 		draw_sprites(bitmap, finalclip);
 
 	draw_layer_roz(screen, m_work_bitmap, finalclip, m_tilemap_A);
+	if(m_mosaic_aplane > 0)
+		ygv608_draw_mosaic(m_work_bitmap, finalclip, m_mosaic_aplane);
 
 	if(m_planeA_trans_enable == true)
 		copybitmap_trans( bitmap, m_work_bitmap, 0, 0, 0, 0, finalclip, 0);
@@ -1941,8 +1965,8 @@ WRITE8_MEMBER( ygv608_device::screen_ctrl_10_w )
 	// check mosaic
 	m_mosaic_bplane = (data & 0xc) >> 2;
 	m_mosaic_aplane = data & 3;
-	if(m_mosaic_aplane || m_mosaic_bplane)
-		popmessage("Mosaic effect %02x %02x",m_mosaic_aplane,m_mosaic_bplane);
+//	if(m_mosaic_aplane || m_mosaic_bplane)
+//		popmessage("Mosaic effect %02x %02x",m_mosaic_aplane,m_mosaic_bplane);
 }
 
 // R#11R - screen control 11
diff --git a/src/mame/video/ygv608.h b/src/mame/video/ygv608.h
index 8a1fee7278c..95519c3a00d 100644
--- a/src/mame/video/ygv608.h
+++ b/src/mame/video/ygv608.h
@@ -127,6 +127,7 @@ private:
 	void register_state_save();
 	void draw_sprites(bitmap_ind16 &bitmap, const rectangle &cliprect);
 	void draw_layer_roz(screen_device &screen, bitmap_ind16 &bitmap, const rectangle &cliprect, tilemap_t *source_tilemap);
+	void ygv608_draw_mosaic(bitmap_ind16 &bitmap, const rectangle &cliprect, int n);
 
 	uint8_t m_namcond1_gfxbank;