(FORTUNE Magazine) – For the past 2 1/2 years, fledgling television networks UPN and WB have been fighting each other for the title of "fifth network." Both claim higher ratings and better distribution, and both have big corporate parents pouring money into them (WB has Time Warner, which also owns FORTUNE, and UPN has Viacom). WB's mascot is a cartoon frog; UPN's president occasionally wears a lapel pin depicting a bloody frog impaled on a dagger. But this rivalry is beside the point: the real fifth network is Univision, a Spanish-language broadcaster based in Los Angeles.

Univision has quietly made itself into a small but agile TV power. It reaches 92% of Spanish-speaking households and scored higher ratings than UPN and WB last season. Even more impressive, during the past year Univision has challenged the big four networks, winning the prime-time ratings race in Miami last November and scoring well in L.A. and Chicago. In May, its pitch to advertisers at the annual industry gathering in New York City raised millions from the likes of AT&T, Sears, and Procter & Gamble. "Hispanics have a higher propensity to respond to direct pitches because there aren't as many things being thrown their way," says Glad Perez, a manager of Hispanic marketing at AT&T. "They tend to consider ads more closely."

Univision's success began in 1992 when two Latin America-based programmers, Televisa and Venevision, joined media mogul Jerrold Perenchio to buy Univision from Hallmark, the greeting-card company. The two Latin-American networks provide Univision with two-thirds of its programming, which saves the network in production costs, says Frank Bodenchak, an analyst at Morgan Stanley. (Some of these recycled shows do more than just save money. The network's novelas, nightly soap operas featuring women with little dresses and big hair who fight over the men they love, are huge hits.) By securing these partners, Univision blocked its main Spanish-language competition, Telemundo, from the primary sources of programming. Univision usually attracts more than 80% of Spanish-speaking viewers and among this group accounts for 15 of the top 20 shows.

Univision's daytime schedule is similar to the Anglo networks'. It starts the morning with a Today-type show, followed by talk shows, newsmagazines, news, and novelas. On Saturday comes one of the most popular shows, Sabado Gigante ("Giant Saturday"), a four-hour variety show featuring contests, amateur performers, and of course, women with little dresses and big hair. Host Don Francisco, ne Mario Kreutzberger, sings advertising jingles during the show and often gets the audience to join in.

The network's production quality is improving, but its shows look dated--Sabado Gigante's production people seem to have learned their trade by watching Captain & Tennille-era variety shows. The unintended retro look could be troublesome: As more Hispanics become bilingual, they have more programming to choose from. Suddenly, Don Francisco is up against Walker, Texas Ranger on CBS. Fox shows have had particular success with bilingual viewers, especially novela-like Melrose Place and New York Undercover, which has a Latino star.

Even as new competition looms, Univision has a reputation for having strong management (former Housing and Urban Development Secretary Henry Cisneros joined the company as president in January; the industry finds this impressive) and ad-receptive viewers. Wall Street likes Univision and has driven its stock price up about 30% since its IPO in September. If things keep going Univision's way, TV could be looking at a new network gigante.

--Henry Goldblatt