Matías Cahais (born 24 December 1987) is an Argentine football central defender currently playing for Curicó Unido.

After some offers from European clubs, 21 January 2008, Cahais signed a contract for the Dutch club FC Groningen, initially for a one-year-and-a-half deal, with the possibility of a definitive acquisition for a €2 million price, after the first period.

During his presentation ceremony on Groningen, the defender said that, even with the bigger offer from Real Madrid, he opted for signing for a Dutch team because he wanted to make his European career "step for step", and he felt that an Eredivisie club was the right choice to do, as the Dutch league was also the start of the European career of players like Ronaldo, Romário and his compatriot Julio Cruz.

[2] Cahais has represented the Argentina national football team at Under-17 and Under-20 levels.

In 2007, he was selected to play for Argentina at the South American Youth Championship in Paraguay where he scored 2 goals.