diff --git a/sapl/materia/migrations/0026_auto_20180302_1411.py b/sapl/materia/migrations/0026_auto_20180302_1411.py
new file mode 100644
index 000000000..9d401710e
--- /dev/null
+++ b/sapl/materia/migrations/0026_auto_20180302_1411.py
@@ -0,0 +1,20 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.9.13 on 2018-03-02 17:11
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('materia', '0025_auto_20180221_1649'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='numeracao',
+            name='data_materia',
+            field=models.DateField(null=True, verbose_name='Data'),
+        ),
+    ]
diff --git a/sapl/materia/models.py b/sapl/materia/models.py
index 51fbcb855..ab4b3d074 100644
--- a/sapl/materia/models.py
+++ b/sapl/materia/models.py
@@ -515,7 +515,7 @@ class Numeracao(models.Model):
                                       verbose_name=_('Número'))
     ano_materia = models.PositiveSmallIntegerField(verbose_name=_('Ano'),
                                                    choices=RANGE_ANOS)
-    data_materia = models.DateField(verbose_name=_('Data'))
+    data_materia = models.DateField(verbose_name=_('Data'), null=True)
 
     class Meta:
         verbose_name = _('Numeração')
@@ -529,7 +529,7 @@ class Numeracao(models.Model):
     def __str__(self):
         return _('%(numero)s/%(ano)s') % {
             'numero': self.numero_materia,
-            'ano': self.data_materia.year}
+            'ano': self.ano_materia}
 
 
 @reversion.register()