diff --git a/lib/premailer-rails3/hook.rb b/lib/premailer-rails3/hook.rb
index <HASH>..<HASH> 100644
--- a/lib/premailer-rails3/hook.rb
+++ b/lib/premailer-rails3/hook.rb
@@ -6,6 +6,7 @@ module PremailerRails
         html_part = message.body
       )
         premailer = Premailer.new(html_part.body.to_s)
+        plain_text = message.text_part.try(:body).try(:to_s)
 
         # reset the body and add two new bodies with appropriate types
         message.body = nil
@@ -15,8 +16,9 @@ module PremailerRails
           body premailer.to_inline_css
         end
 
+        plain_text = premailer.to_plain_text if plain_text.blank?
         message.text_part do
-          body premailer.to_plain_text
+          body plain_text
         end
       end
     end
Do not override already rendered plain-text mail