The late signing comes after the 36-year-old Spaniard took time to decide consider his options for 2015.
"For me, the BMC Racing Team is my team," said Sanchez who was a key contributor to BMC last season, finishing sixth in the Vuelta a
EspaÃ±a and fifth in Il Lombardia while regularly playing the role of
"I know the riders. I know the team. And I don't like to change much. I prefer one team. As for my fitness, I may not be ready to race tomorrow, but I did a good job at home to stay active. I was riding my mountain bike and doing cyclocross. My level is not good, but it is not bad, either."
BMC sport manager Allan Peiper welcomes SÃ¡nchez's return.
"Everyone is very happy to have Sammy back," Peiper said.
"From a sporting perspective, he gives us that much more depth. We saw last year what a game-changer he can be. This year we expect him to contribute in pretty much the same way, but maybe with a little more focus on the support and development of the big influx of young talent we have brought into the team."
Sanchez's first race will be the Cadel Evans Great Ocean Road Race this weekend where he will race alongside Cadel Evans in the final race of his career.