diff --git a/sapl/protocoloadm/models.py b/sapl/protocoloadm/models.py
index 4f6014733..0823a18a3 100644
--- a/sapl/protocoloadm/models.py
+++ b/sapl/protocoloadm/models.py
@@ -126,7 +126,7 @@ class DocumentoAdministrativo(models.Model):
         choices=YES_NO_CHOICES)
     assunto = models.TextField(verbose_name=_('Assunto'))
     observacao = models.TextField(
-        blank=True, null=True, verbose_name=_('Observação'))
+        blank=True, verbose_name=_('Observação'))
     texto_integral = models.FileField(
         blank=True,
         null=True,