diff --git a/modoboa/core/migrations/0003_user_master_user.py b/modoboa/core/migrations/0003_user_master_user.py
new file mode 100644
index 000000000..9411bdd5c
--- /dev/null
+++ b/modoboa/core/migrations/0003_user_master_user.py
@@ -0,0 +1,20 @@
+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+
+from django.db import models, migrations
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('core', '0002_delete_extension'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='user',
+            name='master_user',
+            field=models.BooleanField(default=False, verbose_name='Allow mailboxes access'),
+            preserve_default=True,
+        ),
+    ]
diff --git a/modoboa/core/models.py b/modoboa/core/models.py
index 5e3bb14e4..2da5825fd 100644
--- a/modoboa/core/models.py
+++ b/modoboa/core/models.py
@@ -49,6 +49,12 @@ class User(PermissionsMixin):
     is_active = models.BooleanField(default=True)
     date_joined = models.DateTimeField(default=timezone.now)
     is_local = models.BooleanField(default=True)
+    master_user = models.BooleanField(
+        ugettext_lazy("Allow mailboxes access"), default=False,
+        help_text=ugettext_lazy(
+            "Allow this administrator to access user mailboxes"
+        )
+    )
     password = models.CharField(ugettext_lazy('password'), max_length=256)
     last_login = models.DateTimeField(
         ugettext_lazy('last login'), default=timezone.now