Under the deal, which kicked off on 1 July, Delaware North will be the exclusive provider of all hospitality and food services at Pride Park, which will be hosting Championship games next season after Derby's relegation from the Premier League.
The company will also provide marketing, sales, catering, conference and hospitality services on non-event days.
Delaware is promising "vast improvements" to the way supporters buy food and drink on a match day, with plans in place to refurbish the public outlets, install new signage and implement a better design to ease customer flows.
Adam Pearson, the chairman at Derby, said: "These improvements are being made with the supporters in mind and with a commitment to improve the match day experience at all levels.
"Derby County sponsors, supporters and fans deserve the services of the best as we work our way back into the Premier League."
Simon Dobson, UK managing director at Delaware North, said that the ten-year deal gave the caterer the opportunity to make an important contribution to the success of the club.
"We know that we begin this contract at the end of a difficult season for Derby County, but we have also felt the optimism, determination and creativity of the club's new ownership group and we want to be there for the long term to help them reach their goals," he said.
By Daniel Thomas
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