diff --git a/uncloud/uncloud_pay/management/commands/handle-overdue-bills.py b/uncloud/uncloud_pay/management/commands/handle-overdue-bills.py
new file mode 100644
index 0000000..f4749f0
--- /dev/null
+++ b/uncloud/uncloud_pay/management/commands/handle-overdue-bills.py
@@ -0,0 +1,43 @@
+from django.core.management.base import BaseCommand
+from uncloud_auth.models import User
+from uncloud_pay.models import Order, Bill
+from uncloud_pay.helpers import get_balance_for, get_payment_method_for
+
+from datetime import timedelta
+from django.utils import timezone
+
+class Command(BaseCommand):
+    help = 'Generate bills and charge customers if necessary.'
+
+    def add_arguments(self, parser):
+        pass
+
+    def handle(self, *args, **options):
+        users = User.objects.all()
+        print("Processing {} users.".format(users.count()))
+        for user in users:
+            balance = get_balance_for(user)
+            if balance < 0:
+                print("User {} has negative balance ({}), checking for overdue bills."
+                        .format(user.username, balance))
+
+                # Get bills DESCENDING by creation date (= latest at top).
+                bills = Bill.objects.filter(
+                        owner=user,
+                        due_date__lt=timezone.now()
+                        ).order_by('-creation_date')
+                overdue_balance = abs(balance)
+                overdue_bills = []
+                for bill in bills:
+                    if  overdue_balance < 0:
+                        break # XXX: I'm (fnux) not fond of breaks!
+
+                    overdue_balance -= bill.amount
+                    overdue_bills.append(bill)
+
+                for bill in overdue_bills:
+                    print("/!\ Overdue bill for {}, {} with amount {}"
+                            .format(user.username, bill.uuid, bill.amount))
+                    # TODO: take action?
+
+        print("=> Done.")