State-owned Budvar has been fighting with Anheuser-Busch for over a century over use of the Budweiser brand name. The legal battle continued when Anheuser-Busch was taken over by Belgium's InBev in 2008 to create the world's largest brewer.
In a statement, the Czech company -- whose full name is Budejovicky Budvar NP -- said the court in Lisbon rejected AB InBev's challenge to an earlier ruling because its Budweiser trademarks could be mistaken for those Budvar had already registered in Portugal.
AB InBev has an option to appeal but has not yet said if it plans to do so.
Spokeswoman Karen Couck said in an emailed statement to the Associated Press that the ruling has not affected AB InBev's sales of its beer "under the established BUD brand in Portugal, as we have been doing for years without challenge or interruption from Budvar."