diff --git a/runtime/doc/change.txt b/runtime/doc/change.txt
--- a/runtime/doc/change.txt
+++ b/runtime/doc/change.txt
@@ -628,6 +628,8 @@
 	    <Esc>   to quit substituting
 	    'a'	    to substitute this and all remaining matches {not in Vi}
 	    'q'	    to quit substituting {not in Vi}
+	    'u'     to undo the previous substitution {not in Vi}
+	    CTRL-L  redraw screen
 	    CTRL-E  to scroll the screen up {not in Vi, not available when
 			compiled without the |+insert_expand| feature}
 	    CTRL-Y  to scroll the screen down {not in Vi, not available when
diff --git a/src/ex_cmds.c b/src/ex_cmds.c
--- a/src/ex_cmds.c
+++ b/src/ex_cmds.c
@@ -4267,6 +4267,8 @@
 #ifdef FEAT_EVAL
     int         save_ma = 0;
 #endif
+    colnr_T     prev_col[256];		/* for placing the cursor after undoing */
+    int		vi_undo;
 
     cmd = eap->arg;
     if (!global_busy)
@@ -4694,7 +4696,8 @@
 
 		    /* When 'cpoptions' contains "u" don't sync undo when
 		     * asking for confirmation. */
-		    if (vim_strchr(p_cpo, CPO_UNDO) != NULL)
+		    vi_undo = (vim_strchr(p_cpo, CPO_UNDO) != NULL);
+		    if (vi_undo)
 			++no_u_sync;
 
 		    /*
@@ -4761,7 +4764,7 @@
 			    /* write message same highlighting as for
 			     * wait_return */
 			    smsg_attr(hl_attr(HLF_R),
-				    (char_u *)_("replace with %s (y/n/a/q/l/^E/^Y)?"), sub);
+				    (char_u *)_("replace with %s (y/n/a/q/l/u/^E/^Y)?"), sub);
 			    msg_no_more = FALSE;
 			    msg_scroll = i;
 			    showruler(TRUE);
@@ -4795,6 +4798,11 @@
 			}
 			if (typed == 'n')
 			    break;
+			if (typed == 'u')
+			{
+			    if (sub_nsubs)
+				break;
+			}
 			if (typed == 'y')
 			    break;
 			if (typed == 'l')
@@ -4809,6 +4817,15 @@
 			    do_ask = FALSE;
 			    break;
 			}
+			/* enable redrawing */
+			if (typed == Ctrl_L)
+			{
+			    temp = RedrawingDisabled;
+			    RedrawingDisabled = 0;
+			    update_topline();
+			    update_screen(CLEAR);
+			    RedrawingDisabled = temp;
+			}
 #ifdef FEAT_INS_EXPAND
 			if (typed == Ctrl_E)
 			    scrollup_clamp();
@@ -4820,9 +4837,47 @@
 #ifdef FEAT_MOUSE
 		    setmouse();
 #endif
-		    if (vim_strchr(p_cpo, CPO_UNDO) != NULL)
+		    if (vi_undo)
 			--no_u_sync;
-
+		    else if (scriptin[curscript] != NULL)
+			    u_sync(TRUE); /* sync undo for test script */
+
+		    if (typed == 'u')
+		    {
+			if (sub_nsubs)
+			{
+			    int idx;
+			    pos_T  p = curwin->w_cursor;
+
+			    if (vi_undo)
+			    {
+				idx = 0;
+				sub_nsubs = 0;
+			    }
+			    else
+				idx = --sub_nsubs;
+
+
+			    /* skip undo message */
+			    temp = global_busy;
+			    global_busy = TRUE;
+			    u_undo(1);
+			    global_busy = temp;
+
+			    sub_firstlnum = lnum = curwin->w_cursor.lnum;
+			    sub_firstline = vim_strsave(ml_get(sub_firstlnum));
+			    /* stay within the arrays bound */
+			    if (idx < 256)
+				/* move cursor to previous match */
+				matchcol = prev_col[idx];
+			    temp = searchit(curwin, curbuf, &p, BACKWARD, sub, 1L, 
+				    SEARCH_KEEP, RE_SEARCH, p.lnum, NULL);
+			    if (sub_nlines && (p.lnum < lnum || temp == FAIL))
+				sub_nlines--;
+
+			    goto skip;
+			}
+		    }
 		    if (typed == 'n')
 		    {
 			/* For a multi-line match, put matchcol at the NUL at
@@ -4940,6 +4995,8 @@
 		(void)vim_regsub_multi(&regmatch,
 				    sub_firstlnum - regmatch.startpos[0].lnum,
 					   sub, new_end, TRUE, p_magic, TRUE);
+		if (sub_nsubs < 256)
+		    prev_col[sub_nsubs] = regmatch.startpos[0].col;
 		sub_nsubs++;
 		did_sub = TRUE;
 
diff --git a/src/testdir/test46.in b/src/testdir/test46.in
--- a/src/testdir/test46.in
+++ b/src/testdir/test46.in
@@ -1,6 +1,13 @@
 Tests for multi-line regexps with ":s". vim: set ft=vim :
 
 STARTTEST
+:" test for undo in interactive replacement
+:/^one/s/\w\+/foobar/gc
+:yyyuq:set cpo-=u
+:/^one/s/\w\+/foobar/gc
+:yyunyyyy:set cpo+=u
 :" test if replacing a line break works with a back reference
 :/^1/,/^2/s/\n\(.\)/ \1/
 :" test if inserting a line break works with a back reference
@@ -25,3 +32,4 @@
 6 e7
 77f
 xxxxx
+one two three four five six
diff --git a/src/testdir/test46.ok b/src/testdir/test46.ok
--- a/src/testdir/test46.ok
+++ b/src/testdir/test46.ok
@@ -11,3 +11,4 @@
 6 ex7
 7x7f
 xxxxx
+foobar two foobar foobar foobar foobar