Drinks company C&C is to become the exclusive distributor for Budweiser and Bud Light in Ireland from July, taking over from Diageo.
Diageo Ireland and Budweiser Brewing Group said the firms' business priorities had evolved.
In a statement, the two companies said it had been a "mutual decision" to end the tie-in. Diageo will continue to brew, market and sell Budweiser and Bud Light until June 30.
C&C, which owns Tennent's NI, will take over sales and distribution of Budweiser in Ireland from July 1.
Budweiser Brewing Group president Paula Lindenberg said that the firm was "proud of all we have achieved together with Diageo and isd looking forward to an exciting next chapter with C&C".
"As we look to the future, we'll be working closely to ensure a smooth transition to our customers and are hugely grateful to Diageo for a positive working relationship over the years," she said.
Diageo Ireland country director Oliver Loomes said that Budweiser Brewing Group and their team had been "fantastic partners over the years".
"I am proud of the work we have done together to build Budweiser into one of the most successful beer brands in Ireland," he added.
"We will, of course, continue to brew, market and distribute Budweiser until the end of June and wish the team at Budweiser Brewing Group the very best in the future."