The Republicans regained the majority of the Senate in the 114th Congress, which started in January 2015; the Republicans had not controlled the Senate since January 2007. They had needed a net gain of at least six seats to obtain a majority. They successfully held all of their seats, and gained nine Democratic - held seats. Republicans defeated five Democratic incumbents:
when did republicans gain control of the senate
in the 114th Congress, which started in January 2015