Bundesliga club Werder Bremen on Sunday confirmed that Hugo Almeida has joined Besiktas Istanbul, dpa reported.
Besiktas have reportedly paid 2 million euros (2.6 million dollars) for the Portugal striker, whose contract with Bremen runs out in the summer.
Bremen official Klaus Allofs said that they had decided to sell the Portuguese international because it was the best option for the club.
"A contract extension was not possible. It was best to try to get some money for him before his contract expires," he said.
The 26-year-old Almeida has agreed a three-and-a-half year deal with Besiktas until the end of the 2014 season.
Almeida has scored nine goals for Bremen this season but has fallen out of favour since his dismissal in the 3-0 victory over St Pauli when he scored a hat-trick.
Bremen are enjoying a poor season, languishing in 14th place in the Bundesliga and eliminated from the Champions League.