diff --git a/loopback/locale/es.json b/loopback/locale/es.json
index 9d4504ce2..e275cbb93 100644
--- a/loopback/locale/es.json
+++ b/loopback/locale/es.json
@@ -81,5 +81,6 @@
 	"This client can't be invoiced": "Este cliente no puede ser facturado",
 	"This ticket can't be invoiced": "Este ticket no puede ser facturado",
 	"That item is not available on that day": "El item no esta disponible para esa fecha",
-	"That item doesn't exists": "That item doesn't exists"
+	"That item doesn't exists": "That item doesn't exists",
+	"You cannot add services to an invoiced ticket": "No puedes añadir servicios a un ticket facturado"
 }
\ No newline at end of file
diff --git a/modules/ticket/back/models/ticket-service.js b/modules/ticket/back/models/ticket-service.js
new file mode 100644
index 000000000..3f54a960e
--- /dev/null
+++ b/modules/ticket/back/models/ticket-service.js
@@ -0,0 +1,12 @@
+const UserError = require('vn-loopback/util/user-error');
+
+module.exports = Self => {
+    Self.observe('before save', async ctx => {
+        if (ctx.isNewInstance) {
+            let ticketId = ctx.instance.ticketFk;
+            let ticket = await Self.app.models.Ticket.findById(ticketId);
+            if (ticket.refFk)
+                throw new UserError('You cannot add services to an invoiced ticket');
+        }
+    });
+};