diff --git a/.gitignore b/.gitignore
index 7e77c9d..b770d78 100644
--- a/.gitignore
+++ b/.gitignore
@@ -3,3 +3,4 @@ git-subtree.xml
 git-subtree.1
 mainline
 subproj
+submodule*
diff --git a/git-subtree.sh b/git-subtree.sh
index ce94d36..d5f4b7e 100755
--- a/git-subtree.sh
+++ b/git-subtree.sh
@@ -8,11 +8,12 @@ if [ $# -eq 0 ]; then
     set -- -h
 fi
 OPTS_SPEC="\
-git subtree add   --prefix=<prefix> <commit>
-git subtree merge --prefix=<prefix> <commit>
-git subtree pull  --prefix=<prefix> <repository> <refspec...>
-git subtree push  --prefix=<prefix> <repository> <refspec...>
-git subtree split --prefix=<prefix> <commit...>
+git subtree add            --prefix=<prefix> <commit>
+git subtree merge          --prefix=<prefix> <commit>
+git subtree pull           --prefix=<prefix> <repository> <refspec...>
+git subtree push           --prefix=<prefix> <repository> <refspec...>
+git subtree split          --prefix=<prefix> <commit...>
+git subtree from-submodule --prefix=<prefix>
 --
 h,help        show the help
 q             quiet
@@ -100,7 +101,7 @@ done
 command="$1"
 shift
 case "$command" in
-	add|merge|pull) default= ;;
+	add|merge|pull|from-submodule) default= ;;
 	split|push) default="--default HEAD" ;;
 	*) die "Unknown command '$command'" ;;
 esac
@@ -554,7 +555,8 @@ cmd_split()
 	eval "$grl" |
 	while read rev parents; do
 		revcount=$(($revcount + 1))
-		say -n "$revcount/$revmax ($createcount)
"
+		say -n "$revcount/$revmax ($createcount)
+"
 		debug "Processing commit: $rev"
 		exists=$(cache_get $rev)
 		if [ -n "$exists" ]; then
@@ -680,4 +682,31 @@ cmd_push()
 	fi
 }
 
+cmd_from-submodule()
+{
+	ensure_clean
+
+	local submodule_sha=$(git submodule status $prefix | cut -d ' ' -f 2)
+
+	# Remove references to submodule.
+	git config --remove-section submodule.$prefix
+	git config --file .gitmodules --remove-section submodule.$prefix
+	git add .gitmodules
+
+	# Move submodule aside.
+	local tmp_repo="$(mktemp -d /tmp/git-subtree.XXXXX)"
+	rm -r $tmp_repo
+	mv $prefix $tmp_repo
+	git rm $prefix
+
+	# Commit changes.
+	git commit -m "Remove '$prefix/' submodule"
+
+	# subtree add from submodule repo.
+	cmd_add_repository $tmp_repo HEAD
+
+	# Remove submodule repo.
+	rm -rf $tmp_repo
+}
+
 "cmd_$command" "$@"
diff --git a/test.sh b/test.sh
index 45237c3..d696a6e 100755
--- a/test.sh
+++ b/test.sh
@@ -338,5 +338,43 @@ git log --pretty=format:'commit: %H' | joincommits |
 	check_equal "$x" 1
 ) || exit 1
 
+# Return to mainline
+cd ../..
+
+
+# from-submodule
+
+make_submodule()
+{
+	cd ..
+	local prefix=$1
+
+	local submodule_path=$(mktemp -d submodule.XXX)
+	cd $submodule_path
+	local submodule_abs_path=$(pwd)
+
+	git init > /dev/null
+	create "sub-file"
+	git commit -m "sub-commit" > /dev/null
+	local submodule_sha=$(git rev-parse HEAD)
+	cd ../mainline
+
+	git submodule add $submodule_abs_path $prefix > /dev/null
+	git submodule update --init > /dev/null
+	git commit -m "Added $prefix." > /dev/null
+
+	echo $submodule_sha
+}
+
+subA_sha=$(make_submodule submodules/subA)
+
+git subtree from-submodule --prefix submodules/subA
+
+check_equal "$(last_commit_message)" "Add 'submodules/subA/' from commit '${subA_sha}'"
+# Submodule should be gone.
+check_equal "$(git submodule status)" ""
+
+rm -rf ../submodule.*
+
 echo
 echo 'ok'