Kimberly-Clark, maker of Huggies disposable diapers, has agreed to become the first advertiser on PBS Kids Sprout, Comcast’s new entry into the suddenly crowded preschool market.

A joint venture with Sesame Workshop, HITS Entertainment and PBS Kids, Sprout’s digital network and Web site are scheduled to launch today. Its programming has been available via video-on-demand since April.

For its investment, estimated at nearly $2 million, Kimberly-Clark as of Oct. 1 will be one of just four advertisers on the network and will also have advertising on Sprout’s VOD and Internet platforms.

Like many advertisers, Kimberly-Clark is looking for innovative ways to engage with its customers, the mothers of preschoolers. “A couple of things really caught our interest with Sprout,” said Brad Santeler, director of the Kimberly-Clark media services group. With the network looking to sign just four advertisers, “it’s a low-clutter, noncompetitive environment.”

The deal gives Kimberly-Clark category exclusivity in diapers, pull-ups, wipes and toiletries and the right of first refusal for other appropriate products and in other markets Spout might enter.

Advertising is limited in preschool programming. Like Nick Jr., Sprout will have only two minutes of ads per hour, and spots will run between shows. Those ads will be aimed at parents rather than at the kids watching. Disney Channel’s Playhouse Disney, which accepts only PBS-style sponsorships, has a partnership with McDonald’s.

Working with Comcast, Mr. Santeler expects his company to be able to best understand the VOD and online landscape and interact with customers across multiple platforms. Ads on the channel and on VOD will steer customers to Kimberly-Clark Web site huggiesbabynetwork.com.

“This really allows us to explore how our consumers are engaging these new technologies,” Mr. Santeler said.

Sprout is the latest entry into the preschool field. Nickelodeon and Disney have been longtime players in the market, and Cartoon Network launched its Tickle U block last month.

Mr. Santeler said Kimberly-Clark will continue advertising on Nickelodeon and plans to advertise on Tickle U. The company is reducing spending on traditional broadcast ads to fund its investment in the new networks aimed specifically at preschool kids and their mothers.

Diana Kerekes, acting general manager for PBS Kids Sprout, said Sprout’s programming is already attracting viewers on VOD. Sprout offers 50 hours of programming, 25 percent of which is refreshed biweekly. Sprout this month added five hours of programming in Spanish.

Sprout is already the top kids programmer on Comcast’s VOD platform, with 5.7 million views in July.

“Our numbers have been increasing every month,” Ms. Kerekes said. “The number of set-top boxes watching is increasing as well. That means it’s not just the same customers watching more ‘Barney.'”

At launch, Sprout’s digital network will have 16 million subscribers on DirecTV, Comcast, Insight, RCE Wave Broadband, Metrocast and Blue Ridge Communications.

Ms. Kerekes said Sprout is the only network offering preschool programming 24 hours a day. “We’re there anytime to help moms have quality programming you can trust.”

Its schedule includes such well-known titles as “Sesame Street,” “Bob the Builder,” “Teletubbies,” and “Thomas & Friends,” and is grouped by daypart, with a breakfast block and a goodnight block that features a live host in between shows.

Even with limited commercials, a preschool channel is “a very viable business model,” she said.

For Nickelodeon, “It’s an excellent business,” said Nickelodeon TV President Cyma Zarghami.

Nickelodeon has its Nick Jr. block, Nick Jr. on CBS Saturday morning and Noggin, a commercial-free digital cable channel with preschool programming from 6 a.m. through 6 p.m. Noggin previously was a joint venture between Nick and the Sesame Workshop, and much of Sprout’s programming used to air on Noggin, she said. But those shows were retired because they underperformed in the ratings.

Ms. Zarghami said she’s seen more advertisers interested in targeting moms, but the big money in this category comes from consumer products. Brands like Nick’s “Dora the Explorer” or “Blue’s Clues” can generate billions of dollars in revenues.

She said she doesn’t know whether all of the new players will stay in the market. For Sprout, distribution will be hard to come by. It took Noggin five years to get into 45 million homes, and Toon Disney just crossed the 50 million subscriber mark.

“It’s a little bit of a crowded space,” she said, but “You can never make enough good stuff for little kids.”