The 33-year-old Argentine had 11 assists in 32 Major League Soccer appearances last season. He was acquired by the Whitecaps last August in a trade with Chivas USA.
"We're very pleased to bring Mauro back," Whitecaps head coach Carl Robinson. "Mauro was a crucial part of our run to the playoffs last season. His experience and leadership will continue to be valuable to our squad."
Rosales, who won Olympic gold with Argentina's U-23 side at the 2004 Athens Games, was named MLS Newcomer of the Year in 2011.
The five-foot-eight 165-pound midfielder had three assists in 11 regular-season games and one playoff start for the Whitecaps.