diff --git a/taiga/projects/migrations/0006_auto_20141029_1040.py b/taiga/projects/migrations/0006_auto_20141029_1040.py
new file mode 100644
index 00000000..b2138812
--- /dev/null
+++ b/taiga/projects/migrations/0006_auto_20141029_1040.py
@@ -0,0 +1,26 @@
+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+
+from django.db import models, migrations
+
+def update_total_milestones(apps, schema_editor):
+    Project = apps.get_model("projects", "Project")
+    for project in Project.objects.filter(total_milestones__isnull=True):
+        project.total_milestones = 0
+        project.save()
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('projects', '0005_membership_invitation_extra_text'),
+    ]
+
+    operations = [
+        migrations.RunPython(update_total_milestones),
+        migrations.AlterField(
+            model_name='project',
+            name='total_milestones',
+            field=models.IntegerField(verbose_name='total of milestones', default=0),
+        ),
+    ]
diff --git a/taiga/projects/models.py b/taiga/projects/models.py
index 67f1a897..45944beb 100644
--- a/taiga/projects/models.py
+++ b/taiga/projects/models.py
@@ -131,7 +131,7 @@ class Project(ProjectDefaults, TaggedMixin, models.Model):
     members = models.ManyToManyField(settings.AUTH_USER_MODEL, related_name="projects",
                                      through="Membership", verbose_name=_("members"),
                                      through_fields=("project", "user"))
-    total_milestones = models.IntegerField(default=0, null=True, blank=True,
+    total_milestones = models.IntegerField(default=0, null=False, blank=False,
                                            verbose_name=_("total of milestones"))
     total_story_points = models.FloatField(default=0, verbose_name=_("total story points"))
 
diff --git a/taiga/projects/serializers.py b/taiga/projects/serializers.py
index 43ae4629..60a63636 100644
--- a/taiga/projects/serializers.py
+++ b/taiga/projects/serializers.py
@@ -179,6 +179,15 @@ class ProjectSerializer(ModelSerializer):
             return is_project_owner(self.context["request"].user, obj)
         return False
 
+    def validate_total_milestones(self, attrs, source):
+        """
+        Check that total_milestones is not null, it's an optional parameter but
+        not nullable in the model. 
+        """
+        value = attrs[source]
+        if value is None:
+            raise serializers.ValidationError("Total milestones must be major or equal to zero")
+        return attrs
 
 class ProjectDetailSerializer(ProjectSerializer):
     roles = serializers.SerializerMethodField("get_roles")