diff --git a/activerecord/lib/active_record/nested_attributes.rb b/activerecord/lib/active_record/nested_attributes.rb
index 40e9281..bfed7b8 100644
--- a/activerecord/lib/active_record/nested_attributes.rb
+++ b/activerecord/lib/active_record/nested_attributes.rb
@@ -4,6 +4,12 @@ module ActiveRecord
       klass.extend(ClassMethods)
     end
 
+    # Map of nested change <tt>reflection => { type => { attr => original value } }</tt>.
+    # We have 3 types of change :created, :updated or :destroyed
+    def nested_changes
+      @nested_changes ||= {}
+    end
+
     private
 
     # Returns +true+ if :allow_destroy was specified and the attributes contains a truthy value for the key '_destroy'.
@@ -32,24 +38,34 @@ module ActiveRecord
 
     # Build new records for each attributes hash, but skip any empty ones.
     def build_new_nested_attributes_records(reflection, new_records)
+      created = []
       new_records.each do |record_attributes|
         next if record_attributes.values.all? { |v| v.blank? }
-        send(reflection.name).build record_attributes
+        record = send(reflection.name).build(record_attributes)
+        created << record.changes if record.changed?
       end
+      nested_changes[reflection.name] = { :created => created } if created.any?
     end
 
     # Assign the attributes to their respective records or destroy them if needed.
     # See #should_destroy_nested_attributes_record?
     def assign_to_or_destroy_nested_attributes_records(reflection, existing_records)
+      destroyed = []
+      updated = []
       existing_records.each do |id, record_attributes|
         #p id, record_attributes
         record = send(reflection.name).detect { |record| record.id == id.to_i }
         if should_destroy_nested_attributes_record?(reflection, record_attributes)
+          destroyed << record.attributes.inject({}) { |h,attr| h[attr.first] = [attr.last,nil]; h } if record.changed?
           record.destroy
         else
           record.attributes = record_attributes
+          updated << record.changes if record.changed?
         end
       end
+      nested_changes[reflection.name] ||= {}
+      nested_changes[reflection.name][:destroyed] = destroyed if destroyed.any?
+      nested_changes[reflection.name][:updated] = updated if updated.any?
     end
 
     module ClassMethods
@@ -64,9 +80,17 @@ module ActiveRecord
       def define_nested_attributes_writer_for_one_to_one_association(reflection)
         define_nested_attributes_writer(reflection) do |attributes|
           if should_destroy_nested_attributes_record?(reflection, attributes)
-            send(reflection.name).destroy
+            record = send(reflection.name)
+            nested_changes[reflection.name] = { :destroy => record.attributes.inject({}) { |h,attr| h[attr.first] = [attr.last,nil]; h } }
+            record.destroy
           else
-            (send(reflection.name) || send("build_#{reflection.name}")).attributes = attributes
+            if record = send(reflection.name)
+              action_type = :updated
+            elsif record = send("build_#{reflection.name}")
+              action_type = :created
+            end
+            record.attributes = attributes
+            nested_changes[reflection.name] = { action_type => record.changes } if record.changed?
           end
         end
       end