The mail company will offer a 20% discount on new or additional mail volumes throughout March and April 2011.
Royal Mail claims the first sale, which ran this spring, was a “success”.
The move is the latest from the postal service designed to boost the take up of direct mail and offset declining mail volumes and falling revenue.
Royal Mail reported a 5% drop in mail volumes for the six months to 30 September, driving operating profit down to £52m.
The organisation hopes initiatives such as the “DM Sale” and Door Drops Online, the recently introduced online campaign planning tool, will boost revenue ahead of its part-privatisation.
Last month, the Government introduced the Postal Services Bill, which paved the way for Royal Mail to be privatised by proposing that private buyers be allowed to buy up to 90% of the business.
The discount covers Mailsort 3 or Sustainable Mail 3 Letter and Large Letter format items.