diff --git a/addons/mass_mailing/views/mass_mailing_views.xml b/addons/mass_mailing/views/mass_mailing_views.xml
index ab86e32d87d..8dfe2e8726e 100644
--- a/addons/mass_mailing/views/mass_mailing_views.xml
+++ b/addons/mass_mailing/views/mass_mailing_views.xml
@@ -645,7 +645,7 @@
                                             groups="mass_mailing.group_mass_mailing_campaign"/>
                                         <field name="campaign_id" invisible="1"
                                             groups="base.group_no_one"/>
-                                        <field name="source_id"
+                                        <field name="source_id" readonly="1"
                                             string="Source"
                                             required="False"
                                             groups="base.group_no_one"/>