diff --git a/builtin-checkout.c b/builtin-checkout.c
index 08c6d8614ae2b619f520616fecd45b24fd866732..1ee23468ff27de8f8d35c15ce6b10ac11995c0f9 100644
--- a/builtin-checkout.c
+++ b/builtin-checkout.c
@@ -565,6 +565,18 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
 		return checkout_paths(source_tree, pathspec);
 	}
 
+	if (opts.new_branch) {
+		struct strbuf buf;
+		strbuf_init(&buf, 0);
+		strbuf_addstr(&buf, "refs/heads/");
+		strbuf_addstr(&buf, opts.new_branch);
+		if (!get_sha1(buf.buf, rev))
+			die("git checkout: branch %s already exists", opts.new_branch);
+		if (check_ref_format(buf.buf))
+			die("git checkout: we do not like '%s' as a branch name.", opts.new_branch);
+		strbuf_release(&buf);
+	}
+
 	if (new.name && !new.commit) {
 		die("Cannot switch branch to a non-commit.");
 	}
diff --git a/t/t7201-co.sh b/t/t7201-co.sh
index fbec70d3c6abff4a97aa205aa10fbf6fe336fa5f..0679abd29d907944c5c246275adfcd760f001d55 100755
--- a/t/t7201-co.sh
+++ b/t/t7201-co.sh
@@ -359,4 +359,14 @@ test_expect_success 'checkout an unmerged path should fail' '
 	test_cmp sample file
 '
 
+test_expect_success 'failing checkout -b should not break working tree' '
+	git reset --hard master &&
+	git symbolic-ref HEAD refs/heads/master &&
+	test_must_fail git checkout -b renamer side^ &&
+	test $(git symbolic-ref HEAD) = refs/heads/master &&
+	git diff --exit-code &&
+	git diff --cached --exit-code
+
+'
+
 test_done