It is 140 years since Ellen Warburton baked the first loaf, and the company is inviting social media users to tell them how many loaves she sold on the first day for a chance to win.
The bread company will post 26 different questions during the promotion period on Facebook and Twitter.
To enter the competition, post the answer to the question under the promotional post including the hashtag #140years.
Chairman of Warburtons, Jonathan Warburton, said: “We are extremely proud to be celebrating such a milestone birthday this year. After 140 years the company is still operated by the Warburtons family and driven by our core family values.”
He added: “I have no doubt that it is these family roots that will continue to help us to go from strength to strength over the next 140 years and beyond.”
Warburtons is the largest bakery brand in the UK, producing more than 2m wax-wrapped loaves, wraps, crumpets, pancakes and bread rolls a day.
In May, Warburtons topped the list of the UK’s most-bought fast moving consumer goods.