diff --git a/lib/onix.rb b/lib/onix.rb
index bc8fee3..9d70498 100644
--- a/lib/onix.rb
+++ b/lib/onix.rb
@@ -68,6 +68,7 @@ def self.two_digit
 require "onix/contributor"
 require "onix/language"
 require "onix/subject"
+require "onix/mainsubject"
 require "onix/audience_range"
 require "onix/imprint"
 require "onix/publisher"
diff --git a/lib/onix/mainsubject.rb b/lib/onix/mainsubject.rb
new file mode 100644
index 0000000..c838ff3
--- /dev/null
+++ b/lib/onix/mainsubject.rb
@@ -0,0 +1,14 @@
+# coding: utf-8
+
+module ONIX
+  class MainSubject
+    include ROXML
+
+    xml_name "MainSubject"
+
+    xml_accessor :mainsubject_scheme_id,  :from => "MainSubjectSchemeIdentifier", :as => Fixnum, :to_xml => ONIX::Formatters.two_digit
+    xml_accessor :subject_scheme_version, :from => "SubjectSchemeVersion"
+    xml_accessor :subject_code,           :from => "SubjectCode"
+    xml_accessor :subject_heading_text,   :from => "SubjectHeadingText"
+  end
+end
diff --git a/lib/onix/product.rb b/lib/onix/product.rb
index 32e68ae..83f05df 100644
--- a/lib/onix/product.rb
+++ b/lib/onix/product.rb
@@ -20,6 +20,7 @@ class Product
     xml_accessor :number_of_pages, :from => "NumberOfPages", :as => Fixnum
     xml_accessor :basic_main_subject, :from => "BASICMainSubject"
     xml_accessor :bic_main_subject, :from => "BICMainSubject"
+    xml_accessor :mainsubject, :from => "MainSubject", :as => ONIX::MainSubject
     xml_accessor :subjects, :from => "Subject", :as => [ONIX::Subject]
     xml_accessor :audience_code, :from => "AudienceCode", :to_xml => ONIX::Formatters.two_digit
     xml_accessor :audience_ranges, :from => "AudienceRange", :as => [ONIX::AudienceRange]
diff --git a/lib/onix/product_identifier.rb b/lib/onix/product_identifier.rb
index cd274e1..a453ec6 100644
--- a/lib/onix/product_identifier.rb
+++ b/lib/onix/product_identifier.rb
@@ -8,5 +8,6 @@ class ProductIdentifier
 
     xml_accessor :product_id_type, :from => "ProductIDType", :as => Fixnum, :to_xml => ONIX::Formatters.two_digit
     xml_accessor :id_value, :from => "IDValue"
+    xml_accessor :id_type_name, :from => "IDTypeName"
   end
 end