Fiorina walked into the Santa Clara County Registrar of Voters office Monday and filed the legal paperwork making her a candidate for the Republican nomination.
She's already been campaigning for months and faces two other well known Republicans Tom Campbell and Chuck Devore for the nomination.
The winner will face off against Democratic incumbent Barbara Boxer. Fiorina, a former Hewlett-Packard CEO, says she's running for Senate to create jobs and return fiscal responsibility to Washington..
