diff --git a/addons/mass_mailing/models/mail_mail.py b/addons/mass_mailing/models/mail_mail.py
index 651d8f07729..c2775ad019b 100644
--- a/addons/mass_mailing/models/mail_mail.py
+++ b/addons/mass_mailing/models/mail_mail.py
@@ -21,6 +21,7 @@
 
 import urlparse
 import werkzeug.urls
+import re
 
 from openerp.tools.translate import _
 from openerp import tools
@@ -80,6 +81,14 @@ class MailMail(osv.Model):
         base = "<base href='%s'>" % domain
         body = tools.append_content_to_html(base, body, plaintext=False, container_tag='div')
 
+        # resolve relative image url to absolute for outlook.com
+        def _sub_relative2absolute(match):
+            return match.group(1) + urlparse.urljoin(domain, match.group(2))
+        # Regex: https://regex101.com/r/aE8uG5/3
+        body = re.sub('(<img(?=\s)[^>]*\ssrc=["\'])(/[^/][^"\']+)', _sub_relative2absolute, body)
+        # Regex: https://regex101.com/r/kT3lD5/2
+        body = re.sub(r'(<[^>]+\bstyle=["\'][^"\']+\burl\([\'"]?)(/[^/\'"][^\'")]+)', _sub_relative2absolute, body)
+
         # generate tracking URL
         if mail.statistics_ids:
             tracking_url = self._get_tracking_url(cr, uid, mail, partner, context=context)