The 34-year-old has extended his stay with the Spanish team by another three years, having first joined them in 2005.
Valverde enjoyed a superb 2014 season, finishing fourth at the Tour de France and third at the recently concluded Vuelta a Espana.
He also won the Fleche Wallonne, Roma Maxima and the Clasica de San Sebastian races, as well as the Vuelta a Andalucia.
"I'm thrilled," Valverde told the team's official website. "It's what both sides wanted...this is my family and we understand [each other] well.
"I feel better than when I was 25. Maturity gives you peace of mind and helps you see everything differently."
The team's general manager, Eusebio Unzue, added: "[Alejandro] is a unique rider. No one is able to maintain focus and a willingness to win that he offers throughout each year."