Advertisers or their agencies must submit 500 words about why their brand wants to advertise on Sundays and why they want to engage with the Mail on Sunday's audience, by 17 June this year.
The competition is open to advertisers who have not advertised in a Sunday newspaper before or to brands which haven't advertised in The Mail on Sunday (MoS) in the past 12 months (the year ending 16 May 2011).
John Teal, advertising director at Mail Newspapers, said: "We are delighted to be providing an opportunity for a new or lapsed Sunday advertiser to take advantage of the unique communications properties which Sunday newspaper advertising brings.
"We want to fund four weeks of advertising within The MoS, a publication which over five million people invite into their precious Sundays every week, to prove how effective this medium is.
The winner of the competition will receive four free full colour pages in the Mail on Sunday, one free full colour page for four consecutive weeks, as well as pre and post campaign effectiveness research and creative pre-testing with a creative consultancy.
Teal said: "We will also be funding a simultaneous campaign for our winning advertiser on the MailOnline to highlight the synergy between these two mediums and the strength of the Mail brand among consumers."
The competition follows MoS's presentation to media agencies last week, where the paper positioned itself as an ecommerce driver and launched its biggest-ever rewards initiative for readers.