diff --git a/openstack_dashboard/dashboards/project/instances/workflows/create_instance.py b/openstack_dashboard/dashboards/project/instances/workflows/create_instance.py
index 9a74ee85fe..5d0ada1e17 100644
--- a/openstack_dashboard/dashboards/project/instances/workflows/create_instance.py
+++ b/openstack_dashboard/dashboards/project/instances/workflows/create_instance.py
@@ -110,7 +110,7 @@ class SetInstanceDetailsAction(workflows.Action):
 
     volume_size = forms.IntegerField(label=_("Device size (GB)"),
                                   initial=1,
-                                  min_value=1,
+                                  min_value=0,
                                   required=False,
                                   help_text=_("Volume size in gigabytes "
                                               "(integer value)."))
@@ -221,9 +221,13 @@ class SetInstanceDetailsAction(workflows.Action):
 
         if source_type in ('image_id', 'volume_image_id'):
             if source_type == 'volume_image_id':
-                if not self.data.get('volume_size', None):
+                volume_size = self.data.get('volume_size', None)
+                if not volume_size:
                     msg = _("You must set volume size")
                     self._errors['volume_size'] = self.error_class([msg])
+                if float(volume_size) <= 0:
+                    msg = _("Volume size must be greater than 0")
+                    self._errors['volume_size'] = self.error_class([msg])
                 if not cleaned_data.get('device_name'):
                     msg = _("You must set device name")
                     self._errors['device_name'] = self.error_class([msg])