Wal-Mart Stores Inc. (WMT) is expanding its $10 prescription mail-delivery program nationwide, a move that shows the world's largest retailer isn't shying away from the pharmacy space.

Wal-Mart's expanded mail-order program, launched as a pilot in Michigan in May, offers customers a 90-day supply of 300 generic drugs for $10. It is similar to one launched nationwide earlier this year by CVS Caremark Corp. (CVS) that offers customers via mail a 90-supply of more than 400 generic drugs for $9.99, plus a $10 sign-up fee.

"The main thing to take away from this is they are not going to let up, especially when they discover a perceived inefficiency in the system," said Andrew Wolf, a drug-store and grocery analyst at BB&T Capital Markets. "This is Wal-Mart, and this is what they do well."

In Wal-Mart's program, no mailing charge is added to the prescription cost and no memberships or enrollment fees are required. In addition to the 300 generic drugs available for $10, the service offers free mail delivery of more than 3,000 other brand and generic prescriptions at other prices.

Wal-Mart has had a mail-order pharmacy program in place for a while, according to spokesperson Christi Gallagher, but decided to expand its $10 program due to the popularity of the pilot program in stores.

Wal-Mart has been ramping up its presence in the health-care arena for a number of years. Most recently, the retail giant has been growing a program it started with Caterpillar Inc. (CAT), which allows companies to buy drugs for their insurance plans directly from pharmacies rather than through third-party pharmacy-benefits management companies, or PBMs. In 2006, Wal-Mart launched $4 fees on a host of generic drugs purchased at its stores, prompting other drug-store chains to offer similar programs.

That said, some drug-store analysts say Wal-Mart's mail-order program expansion alone shouldn't be too much of a threat to drug stores or PBMs, at least in the short term.

"Mail isn't a real driver in this market," said Bernstein analyst Helene Wolk. "Mail as a channel has pretty much stayed at a steady state."

Wolk sees Wal-Mart's expansion of the program as way to appeal to customers who may not live close to one of its roughly 4,100 pharmacy locations.

"I think the problem is people don't like mail," Wolk said, especially as part of a employer mandatory mail program. "They may see this as access, but they may not see it as preferred access."

Mail-order prescription fulfillment gained share earlier this decade, providing a source of earnings growth for PBMs. However, over the last few years, that growth has stalled. While mail-order penetration increased substantially through 2005, it has since plateaued at about 18%, she said.

Still, analysts definitely see Wal-Mart as a worthy pharmacy competitor. The expansion of its mail drug-program adds another weapon to the mass retailer's pharmacy arsenal, and it expands on its strategy to take out the middleman in providing prescriptions cheaply to consumers.

"They want to win in this space, and they are aggressive," said Jefferies analyst Scott Mushkin.

Wal-Mart's shares closed Tuesday at $49.93, down 0.9%. The stock has lost nearly a fifth of its value in the past year.

-By Kelly Nolan, Dow Jones Newswires; 212-416-2167; kelly.nolan@dowjones.com

(Kathy Shwiff contributed to this article.)