Wal-Mart, the world's largest retailer, has decided that it will exclusively sell second generation DVDs in the Blu-Ray format, dealing one in a series of blows to the rival HD DVD format.

The move caps a disappointing week for HD DVD supporters, who also saw consumer electronics chain Best Buy and online video rental company Netflix Inc defect to the Blu-ray camp.

We've listened to our customers, who are showing a clear preference toward Blu-ray products and movies with their purchases, said Gary Severson, a Wal-Mart senior vice president.

Wal-Mart will phase out HD DVD's over the next few months, selling only Blu Ray discs by June.

The move affects 4,000 Wal-Mart and Sam's Club stores in the United States, as well as related online sites. The stores will continue to sell traditional DVD players and movies.

The so-called format war pitted Sony backed Blu-Ray discs against Toshiba's HD-DVD. Like the VHS-betamax format war in the 1980's, the battled posed a problem for retailers who had to stock shelves with both types of media and dealt with complaints and confusion from consumers.

Sony has taken a considerable lead in the format rivalry in recent months, gaining the endorsement of The Walt Disney Co., Sony Corp.'s Sony Pictures, News Corp.'s Twentieth Century Fox, Metro-Goldwyn-Mayer and Time Warner Inc.'s Warner Bros. Entertainment.

The format has gained leverage with sales rising of the popular game system from Sony, the Playstation 3, which sports a Blu-ray player internally.

Toshiba has secured agreements with studios including NBC Universal's Universal Pictures, Viacom Inc's Paramount Pictures and DreamWorks Animation SKG Inc.

Next-generation DVDs and players, boasting better picture quality and more capacity, were expected to help revive the $24 billion global home DVD market.

Microsoft Corp's Xbox 360 also currently works only with HD DVD. However, Microsoft said in January it could consider supporting Blu-ray technology at consumers' behest.

Toshiba could not be reached to comment on Wal-Mart's move.