By Krystyna Rudzki

LONDON (AP) _ Five of the world's top marathons have combined to create a two-year series that will award $500,000 US to the men's and women's winners.

Organizers of the Boston, London, Berlin, Chicago and New York City marathons said Monday that the series _ called World Marathon Majors _ would increase the prestige and promotion of the 42.2-kilometre races.

The Olympic and world championship marathons will also count in the series, which starts with the Boston Marathon on April 17.

``This is one of the most significant changes in the history of our sport,'' London Marathon race director Dave Bedford said, adding that discussions of a world series began three years ago.

Men and women will be scored separately, getting points by placing among the top five in each race: 25 points for a win, 15 points for second, 10 for third, five for fourth and one for fifth.

Athletes would have to complete three races over the two years to be eligible, but only four results will count.

If there is a tie, the winner of any head-to-head competition between the contending athletes in one of the eligible races will get the top prize. If they do not race against each other, the five race directors will choose the winner by a majority vote.

``I feel for the first time that our efforts, our contributions have been recognized,'' marathon world record holder Paul Tergat said. ``We feel that in marathon always, to be able to compete effectively, we need to have this kind of competitiveness.''

The two-year scoring periods will overlap, allowing the group to award prizes on an annual basis following the first winners in 2007.

``Our races are to our sport what Wimbledon and the Australian, U.S. and French Opens are to tennis and what the Masters, U.S., and British Opens and the PGA Championship are to golf,'' New York City Marathon race director Mary Wittenberg said.

Paula Radcliffe, who has won the London, Chicago and New York marathons, said the move was a ``big step forward'' for the sport.

``The results can only be positive and having experienced three of the events involved, I'm convinced that their combined expertise will help the sport immensely,'' Radcliffe said.

Bedford said the series will try to find a sponsor to double the prize money to $1 million for each winner in 2007-08. All five marathons have contributed equally to the first series' $1 million total purse.

Bedford said the series would welcome additional marathons that showed ``the right level and standard to add to our competition.''

He added that the International Association of Athletic Federations and the International Olympic Committee supported the move.

This year's London Marathon is scheduled for April 23, the Berlin Marathon is Sept. 24, the Chicago Marathon is Oct. 22 and the New York City Marathon is Nov. 5. In 2006, the world championship marathons in Osaka, Japan, will also be counted.