DAYTON, Ohio (Reuters) - Republican John McCain picked Alaska Gov. Sarah Palin as his running mate on Friday, a senior campaign official said, in a surprise choice that could help him appeal to women voters.

The choice of Palin, 44, will be unveiled later on Friday in a rally in Dayton as McCain grabs the political focus away from Democratic rival Barack Obama one day after Obama accepted his party's presidential nomination.

McCain and Palin will face Obama and his No. 2, Joe Biden, in the November 4 presidential election.

The pick followed days of speculation about McCain's choice, with most of the better-known contenders like former Massachusetts Gov. Mitt Romney slowly eliminated over the last 24 hours.

Palin is a conservative first-term governor of Alaska with strong anti-abortion views and a record of fiscal conservatism. She is an avid sportswoman who would bring youth and vitality to the ticket. McCain turns 72 on Friday.

Palin is not well-known nationally, and that could cut into McCain's argument that Obama is too inexperienced to handle the White House. But she could help him appeal to disaffected supporters of Democrat Hillary Clinton, who lost a bruising primary to Obama.

In his acceptance speech on Thursday, Obama directly attacked McCain and linked him to what he called the failed Republican economic policies of President George W. Bush.

Palin, former mayor of the town of Wasilla, built a reputation as a reformer in a state that recently has been hit with corruption scandals. Elected in 2006, she is Alaska's first woman governor.

Palin and her husband, Todd, have five children, ranging in age from 18 years to 4 months.

By Jeff Mason, Reuters, August 29, 2008