diff --git a/sapl/sessao/migrations/0021_auto_20180417_1209.py b/sapl/sessao/migrations/0021_auto_20180417_1209.py
new file mode 100644
index 000000000..51993cfdc
--- /dev/null
+++ b/sapl/sessao/migrations/0021_auto_20180417_1209.py
@@ -0,0 +1,26 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.9.11 on 2018-04-17 15:09
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('sessao', '0020_auto_20180416_1424'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='expedientemateria',
+            name='sessao_plenaria',
+            field=models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, to='sessao.SessaoPlenaria'),
+        ),
+        migrations.AlterField(
+            model_name='ordemdia',
+            name='sessao_plenaria',
+            field=models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, to='sessao.SessaoPlenaria'),
+        ),
+    ]
diff --git a/sapl/sessao/models.py b/sapl/sessao/models.py
index c10d3e03d..13e55aea7 100644
--- a/sapl/sessao/models.py
+++ b/sapl/sessao/models.py
@@ -231,7 +231,7 @@ class AbstractOrdemDia(models.Model):
     )
 
     sessao_plenaria = models.ForeignKey(SessaoPlenaria,
-                                        on_delete=models.PROTECT)
+                                        on_delete=models.CASCADE)
     materia = models.ForeignKey(MateriaLegislativa,
                                 on_delete=models.PROTECT,
                                 verbose_name=_('Matéria'))