diff --git a/plugins/custom_forms/db/migrate/20130823151900_associate_fields_to_alternatives.rb b/plugins/custom_forms/db/migrate/20130823151900_associate_fields_to_alternatives.rb
index 0cf7d67..1c3882a 100644
--- a/plugins/custom_forms/db/migrate/20130823151900_associate_fields_to_alternatives.rb
+++ b/plugins/custom_forms/db/migrate/20130823151900_associate_fields_to_alternatives.rb
@@ -15,14 +15,18 @@ class AssociateFieldsToAlternatives < ActiveRecord::Migration
     end
 
     CustomFormsPlugin::Answer.find_each do |answer|
-      labels = []
-      answer.value.split(',').each do |value|
-        labels << answer.field.choices.invert[value]
-      end
-      labels.compact!
-      if labels.present?
-        answer.value = answer.field.alternatives.where('label IN (?)', labels).map(&:id).join(',')
-        answer.save!
+      # Avoid crash due to database possible inconsistency on submissions without form
+      begin
+        labels = []
+        answer.value.split(',').each do |value|
+          labels << answer.field.choices.invert[value]
+        end
+        labels.compact!
+        if labels.present?
+          answer.value = answer.field.alternatives.where('label IN (?)', labels).map(&:id).join(',')
+          answer.save!
+        end
+      rescue
       end
     end
 
diff --git a/plugins/custom_forms/db/migrate/20140505131703_remove_submissions_without_form.rb b/plugins/custom_forms/db/migrate/20140505131703_remove_submissions_without_form.rb
new file mode 100644
index 0000000..696ece4
--- /dev/null
+++ b/plugins/custom_forms/db/migrate/20140505131703_remove_submissions_without_form.rb
@@ -0,0 +1,11 @@
+class RemoveSubmissionsWithoutForm < ActiveRecord::Migration
+  def self.up
+    CustomFormsPlugin::Submission.find_each do |submission|
+      submission.destroy if submission.form.nil?
+    end
+  end
+
+  def self.down
+    say "This migration is irreversible."
+  end
+end
diff --git a/plugins/custom_forms/lib/custom_forms_plugin/form.rb b/plugins/custom_forms/lib/custom_forms_plugin/form.rb
index 0eed935..9b67478 100644
--- a/plugins/custom_forms/lib/custom_forms_plugin/form.rb
+++ b/plugins/custom_forms/lib/custom_forms_plugin/form.rb
@@ -4,7 +4,7 @@ class CustomFormsPlugin::Form < Noosfero::Plugin::ActiveRecord
   has_many :fields, :order => 'position', :class_name => 'CustomFormsPlugin::Field', :dependent => :destroy
   accepts_nested_attributes_for :fields, :allow_destroy => true
 
-  has_many :submissions, :class_name => 'CustomFormsPlugin::Submission'
+  has_many :submissions, :class_name => 'CustomFormsPlugin::Submission', :dependent => :destroy
 
   serialize :access
 
diff --git a/plugins/custom_forms/test/unit/custom_forms_plugin/form_test.rb b/plugins/custom_forms/test/unit/custom_forms_plugin/form_test.rb
index f44f1ca..1b23413 100644
--- a/plugins/custom_forms/test/unit/custom_forms_plugin/form_test.rb
+++ b/plugins/custom_forms/test/unit/custom_forms_plugin/form_test.rb
@@ -260,4 +260,18 @@ class CustomFormsPlugin::FormTest < ActiveSupport::TestCase
     form2.destroy
     assert_includes Task.canceled, task2
   end
+
+  should 'destroy submissions after form is destroyed' do
+    form = CustomFormsPlugin::Form.create!(:profile => fast_create(Profile), :name => 'Free Software')
+    s1 = CustomFormsPlugin::Submission.create!(:form => form, :profile => fast_create(Profile))
+    s2 = CustomFormsPlugin::Submission.create!(:form => form, :profile => fast_create(Profile))
+    form.destroy
+
+    assert_raise ActiveRecord::RecordNotFound do
+      s1.reload
+    end
+    assert_raise ActiveRecord::RecordNotFound do
+      s2.reload
+    end
+  end
 end
--
libgit2 0.21.2