diff --git a/Documentation/config.txt b/Documentation/config.txt
index ad22cb875e54057d7a8246b7c28f44ff90cfd14a..27cb7f14080210fac4dc9b0966dee326aeeaf394 100644
--- a/Documentation/config.txt
+++ b/Documentation/config.txt
@@ -715,6 +715,13 @@ format.thread::
 	A true boolean value is the same as `shallow`, and a false
 	value disables threading.
 
+format.signoff::
+    A boolean value which lets you enable the `-s/--signoff` option of
+    format-patch by default. *Note:* Adding the Signed-off-by: line to a
+    patch should be a conscious act and means that you certify you have
+    the rights to submit this work under the same open source license.
+    Please see the 'SubmittingPatches' document for further discussion.
+
 gc.aggressiveWindow::
 	The window size parameter used in the delta compression
 	algorithm used by 'git-gc --aggressive'.  This defaults
diff --git a/Documentation/git-format-patch.txt b/Documentation/git-format-patch.txt
index db3bdb5657e4c4c55122ec7f0cd735e623f1dec2..eb2fbcff1a103c2b973eccbb449a20d3b68f157f 100644
--- a/Documentation/git-format-patch.txt
+++ b/Documentation/git-format-patch.txt
@@ -205,6 +205,7 @@ more than one.
 	numbered = auto
 	cc = <email>
 	attach [ = mime-boundary-string ]
+	signoff = true
 ------------
 
 
diff --git a/builtin-log.c b/builtin-log.c
index 27bc0dce23d364bd763b7ca92316eef5966c5908..eb2c0541b5ab833fb5c5f9b73eaa752d2e80e9d0 100644
--- a/builtin-log.c
+++ b/builtin-log.c
@@ -465,6 +465,7 @@ static void add_header(const char *value)
 #define THREAD_SHALLOW 1
 #define THREAD_DEEP 2
 static int thread = 0;
+static int do_signoff = 0;
 
 static int git_format_config(const char *var, const char *value, void *cb)
 {
@@ -514,6 +515,10 @@ static int git_format_config(const char *var, const char *value, void *cb)
 		thread = git_config_bool(var, value) && THREAD_SHALLOW;
 		return 0;
 	}
+	if (!strcmp(var, "format.signoff")) {
+		do_signoff = git_config_bool(var, value);
+		return 0;
+	}
 
 	return git_log_config(var, value, cb);
 }
@@ -865,13 +870,7 @@ int cmd_format_patch(int argc, const char **argv, const char *prefix)
 		}
 		else if (!strcmp(argv[i], "--signoff") ||
 			 !strcmp(argv[i], "-s")) {
-			const char *committer;
-			const char *endpos;
-			committer = git_committer_info(IDENT_ERROR_ON_NO_NAME);
-			endpos = strchr(committer, '>');
-			if (!endpos)
-				die("bogus committer info %s", committer);
-			add_signoff = xmemdupz(committer, endpos - committer + 1);
+			do_signoff = 1;
 		}
 		else if (!strcmp(argv[i], "--attach")) {
 			rev.mime_boundary = git_version_string;
@@ -925,6 +924,16 @@ int cmd_format_patch(int argc, const char **argv, const char *prefix)
 	}
 	argc = j;
 
+	if (do_signoff) {
+		const char *committer;
+		const char *endpos;
+		committer = git_committer_info(IDENT_ERROR_ON_NO_NAME);
+		endpos = strchr(committer, '>');
+		if (!endpos)
+			die("bogus committer info %s", committer);
+		add_signoff = xmemdupz(committer, endpos - committer + 1);
+	}
+
 	for (i = 0; i < extra_hdr_nr; i++) {
 		strbuf_addstr(&buf, extra_hdr[i]);
 		strbuf_addch(&buf, '\n');