By Mark Felsenthal

WASHINGTON (Reuters) - President Barack Obama on Wednesday picked Indiana University to win the NCAA annual men's college basketball tournament, joining in the "March Madness" office pool craze that sweeps America every spring.

The president, an avid sports fan, forecast that Indiana would defeat the widely favored University of Louisville in the championship game.

"I think this is Indiana's year," he said in an interview on ESPN, the sports cable network.

Obama began a three day trip to the Middle East on Wednesday and taped the interview on Tuesday.

Millions of Americans are obsessed with the annual National Collegiate Athletic Association basketball tournament, which pits the nation's top teams against one another in 67 games over two weeks.

Betting in office pools is widespread, and celebrities and analysts share and discuss their picks, known as brackets.

The national champion will be crowned on March 31 in Atlanta.

The president was a backup player on a high school basketball team that won a state championship and continues to play in reportedly vigorous games of pickup basketball. He has shown a detailed knowledge of college basketball players, coaches and teams in explaining his picks.

Last year, Obama missed picking the winner, the University of Kentucky, which he predicted would advance to the final but would lose to the University of North Carolina.

However, UNC lost in an earlier round.

(Reporting by Mark Felsenthal; Editing by Vicki Allen)