diff --git a/git-am.sh b/git-am.sh
index a391254a70..75886a8f2f 100755
--- a/git-am.sh
+++ b/git-am.sh
@@ -327,11 +327,20 @@ do
 			echo "Patch is empty.  Was it split wrong?"
 			stop_here $this
 		}
-		SUBJECT="$(sed -n '/^Subject/ s/Subject: //p' "$dotest/info")"
-		case "$keep_subject" in -k)  SUBJECT="[PATCH] $SUBJECT" ;; esac
+		if test -f "$dotest/rebasing" &&
+			commit=$(sed -e 's/^From \([0-9a-f]*\) .*/\1/' \
+				-e q "$dotest/$msgnum") &&
+			test "$(git cat-file -t "$commit")" = commit
+		then
+			git cat-file commit "$commit" |
+			sed -e '1,/^$/d' >"$dotest/msg-clean"
+		else
+			SUBJECT="$(sed -n '/^Subject/ s/Subject: //p' "$dotest/info")"
+			case "$keep_subject" in -k)  SUBJECT="[PATCH] $SUBJECT" ;; esac
 
-		(printf '%s\n\n' "$SUBJECT"; cat "$dotest/msg") |
-			git stripspace > "$dotest/msg-clean"
+			(printf '%s\n\n' "$SUBJECT"; cat "$dotest/msg") |
+				git stripspace > "$dotest/msg-clean"
+		fi
 		;;
 	esac
 
diff --git a/t/t3408-rebase-multi-line.sh b/t/t3408-rebase-multi-line.sh
new file mode 100755
index 0000000000..e12cd578e8
--- /dev/null
+++ b/t/t3408-rebase-multi-line.sh
@@ -0,0 +1,41 @@
+#!/bin/sh
+
+test_description='rebasing a commit with multi-line first paragraph.'
+
+. ./test-lib.sh
+
+test_expect_success setup '
+
+	>file &&
+	git add file &&
+	test_tick &&
+	git commit -m initial &&
+
+	echo hello >file &&
+	test_tick &&
+	git commit -a -m "A sample commit log message that has a long
+summary that spills over multiple lines.
+
+But otherwise with a sane description."
+
+	git branch side &&
+
+	git reset --hard HEAD^ &&
+	>elif &&
+	git add elif &&
+	test_tick &&
+	git commit -m second
+
+'
+
+test_expect_success rebase '
+
+	git checkout side &&
+	git rebase master &&
+	git cat-file commit HEAD | sed -e "1,/^$/d" >actual &&
+	git cat-file commit side@{1} | sed -e "1,/^$/d" >expect &&
+	test_cmp expect actual
+
+'
+
+test_done