diff --git a/beesdoo_shift/models/planning.py b/beesdoo_shift/models/planning.py
index 5b6c47b..d7ea850 100644
--- a/beesdoo_shift/models/planning.py
+++ b/beesdoo_shift/models/planning.py
@@ -178,3 +178,23 @@ class TaskTemplate(models.Model):
                 })
 
         return tasks
+
+    @api.onchange('worker_ids')
+    def check_for_multiple_shifts(self):
+        original_ids = {worker.id for worker in self._origin.worker_ids}
+
+        warnings = []
+        for worker in self.worker_ids:
+            if worker.id not in original_ids:
+                shifts = [shift.name for shift in worker.subscribed_shift_ids if shift.id != self.id]
+                if shifts:
+                    warnings.append(
+                        worker.name + _(' is already assigned to ') + ", ".join(shifts))
+
+        if warnings:
+            return {
+                'warning': {
+                    'title': _("Warning"),
+                    'message': "\n".join(warnings)
+                }
+            }
diff --git a/beesdoo_shift/wizard/subscribe.py b/beesdoo_shift/wizard/subscribe.py
index dc80758..38053f6 100644
--- a/beesdoo_shift/wizard/subscribe.py
+++ b/beesdoo_shift/wizard/subscribe.py
@@ -41,6 +41,15 @@ class Subscribe(models.TransientModel):
                             .info_session)
         return session_followed
 
+    def _get_shift(self):
+        shifts = self.env['res.partner'].browse(self._context.get('active_id')).subscribed_shift_ids
+        if shifts:
+            return shifts[0]
+        return
+
+    def _get_nb_shifts(self):
+        return len(self.env['res.partner'].browse(self._context.get('active_id')).subscribed_shift_ids)
+
     def _get_super(self):
         return self.env['res.partner'].browse(self._context.get('active_id')).super
 
@@ -62,7 +71,8 @@ class Subscribe(models.TransientModel):
         ], default=_get_mode
     )
     exempt_reason_id = fields.Many2one('cooperative.exempt.reason', 'Exempt Reason')
-    shift_id = fields.Many2one('beesdoo.shift.template')
+    shift_id = fields.Many2one('beesdoo.shift.template', default=_get_shift)
+    nb_shifts = fields.Integer(string='Number of shifts', default=_get_nb_shifts)
     reset_counter = fields.Boolean(default=_get_reset_counter_default)
     reset_compensation_counter = fields.Boolean(default=False)
     unsubscribed = fields.Boolean(default=False, string="Are you sure to unsubscribe this cooperator")
diff --git a/beesdoo_shift/wizard/subscribe.xml b/beesdoo_shift/wizard/subscribe.xml
index 3a10cb7..97b0333 100644
--- a/beesdoo_shift/wizard/subscribe.xml
+++ b/beesdoo_shift/wizard/subscribe.xml
@@ -16,12 +16,16 @@
                     <field name="working_mode" />
                     <field name="exempt_reason_id" attrs="{'invisible':[('working_mode', '!=', 'exempt')]}"/>
                     <field name="shift_id" domain="[('remaining_worker', '>', 0)]" attrs="{'invisible': [('working_mode', '!=', 'regular')]}"/>
+                    <field name="nb_shifts" attrs="{'invisible': True}"/>
                     <field name="irregular_start_date" attrs="{'invisible': [('working_mode', '!=', 'irregular')]}" />
                     <field name="super" />
                     <field name="reset_counter" />
                     <field name="reset_compensation_counter" /> <!-- TODO access right -->
                 </group>
                 <footer>
+                    <div class="alert alert-danger" role="alert" attrs="{'invisible': [('nb_shifts', '&lt;', 2)]}">
+                      Current worker has more than one shift, subscribing him to a new shift will erase all previous shifts.
+                    </div>
                     <button type="object" name="subscribe"
                         string="Confirm" class="oe_highlight" attrs="{'invisible': [('unsubscribed', '=', True)]}" />
                     <button type="object" name="unsubscribe"