diff --git a/app/models/metadata_document_date.rb b/app/models/metadata_document_date.rb
index f6ad7d0..82126ba 100644
--- a/app/models/metadata_document_date.rb
+++ b/app/models/metadata_document_date.rb
@@ -11,6 +11,19 @@ class MetadataDocumentDate < MetadataTemplate
     document.date
   end
 
+  # Siempre es obligatorio
+  def required
+    true
+  end
+
+  def validate
+    super
+
+    errors << I18n.t('metadata.date.invalid_format') unless valid_format?
+
+    errors.empty?
+  end
+
   # El valor puede ser un Date, Time o una String en el formato
   # "yyyy-mm-dd"
   #
@@ -24,8 +37,6 @@ class MetadataDocumentDate < MetadataTemplate
       case self[:value]
       when String
         begin
-          raise Date::Error unless /\A\d{2,4}-\d{1,2}-\d{1,2}\z/ ~= self[:value]
-
           Date.iso8601(self[:value]).to_time
         rescue Date::Error
           value_from_document || default_value
@@ -34,4 +45,13 @@ class MetadataDocumentDate < MetadataTemplate
         value_from_document || default_value
       end
   end
+
+  private
+
+  def valid_format?
+    return true if self[:value].is_a?(Time)
+
+    @valid_format_re ||= /\A\d{2,4}-\d{1,2}-\d{1,2}\z/
+    @valid_format_re =~ self[:value].to_s
+  end
 end