diff --git a/gitflow-sh-setup b/gitflow-sh-setup
index 3181c3f..f24025d 100755
--- a/gitflow-sh-setup
+++ b/gitflow-sh-setup
@@ -50,6 +50,13 @@
 	fi
 }
 
+gitflow_require_branch_absent() {
+	echo "$ALL_BRANCHES" | grep "^$1\$" 2>/dev/null >/dev/null
+	if [ $? -eq 0 ]; then
+		die "Branch '$1' already exists."
+	fi
+}
+
 #
 # gitflow_test_branches_equal()
 #