Al Capp, 70, who created the comic strip "Li'l Abner," and endowed American popular culture with the mythical hillbilly realm of Dogpatch, died last night in Cambridge, Mass.

"Li'l Abner," with its amiable yokels, beautiful women and satirical symbols of human frailty, pomposity and disreputability, first appeared in 1934, and at its peak was carried in 900 newspapers.

Mr. Capp died at Mt. Auburn Hospital after a long illness, his attorney said. The cause of death was not released, but it was known that Mr. Capp suffered from emphysema, which had been given as one of the reasons for his decision in 1977 to retire and abandon the strip.

Born in the Depression, the strip had long since passed the peak of its popularity when Mr. Capp gave it up. America had changed, readers' interests had changed, and Mr. Capp's philosophy was seen as increasingly conservative. The targets of his satire were no longer the same, and the vitality seemed to have ebbed from "Li'l Abner."

Mr. Capp said he "could see my stuff didn't have the joy it used to have.

"I wasn't having fun with it anymore," he said. "It was becoming a chore. I grew more and more tired of drawing the strip, and the strip began to show it. So finally I said 'What the hell' and quit."

In his prime, Mr Capp was called one of the greatest cartoonists the nation had produced. "Li'l Abner," vividly drawn, rich and vigorous in character and comic invention, was the delight of millions who followed religiously the rollicking adventures of the hero -- 6-foot 3-inch Li'L Abner Yokum, a kind of latter-day version of the noble savage of myth and legend.

Life in Mr. Capp's mythical hillbilly domain was graced and complicated for Abner by the beautiful and long-pursuing Daisy Mae, who eventually became his wife, and by an assortment of outrageously outlandish friends, relatives and fellow citizens, who included Abner's redoubtable "mammy," Pansy Yokum, as well as characters with such names as Hairless Joe, Lonesome Polecat, and Moonbeam McSwine.

Over the years, loyal followers of "Li'l Abner" also encountered the zoot-suited Evil Eye Fleagle, and the unpronounceable Joe Blpftsk, who walked about under a visible and perpetual storm cloud.

In addition, the strips featured the prototypical plutocrat J. Roaringham Fatback, and his arch enemies, the lovable Shmoos, which happliy rolled over and died when anyone wanted to eat them.

Another character. Sen. Jack S. Phogbound, seemed the epitome of a fatuous and flatulent unreconstructed rural politician.

When the strip was at the peak of its popularity Mr. Capp's zest and zaniness seemed to make him immune from any possible accusation of impropriety, poor taste, or excessive audacity. Those who might have felt themselves the offended models for Sen. Phogbound were not widely heard.

The pompous and bombastic Gen. Bullmoose, who might have been viewed as a symbol of the military-industrial complex, was apparently accepted as a figure of fun.

Fearless Fosdick, an endearingly empty-headed detective, was clearly a parody of the famed Dick Tracy, a creation of one of Mr. Capp's fellow cartoonists, but his appearance in the strip caused no outcry.

"Li'l Abner" gave American Sadie Hawkins Day, a Dogpatch celebration in which eligible males might be married if caught by pursuing females. "Li'l Abner" was made into a long-running Broadway show in the 1950s and then a movie.

In time, Mr. Capp's political views and social philosophy, as embodied in the strip, seemed to become increasingly conservative, and his work showed a growing disillusion with such phenomena of the 1960s and early 1970s as student protests.

And increasingly, as the strip came to be seen as less the freewheeling product of a comic genius than a platform for the not always palatable views of its creator, its popularity appeared to diminish.

Alfred Gerald Caplin, whose name was to be shortened later to Al Capp, was born in New Haven, Conn., Sept. 28, 1909, and moved with his family shortly afterward to Bridgeport, Conn., where he went to the public schools.

By the time he was 11 years old, he was drawing and selling his own comic strips to neighborhood children.

About a year later, while on a visit to New Haven, he was injured in a streetcar accident and as a consequence lost his right leg.

At Bridgeport High School, he claimed to have set a record for mathematical incompetence by flunking geometry nine times. After high school he studied art at a variety of institutions, including the Philadelphia Museum of Fine Arts, Boston University and Harvard University.

In 1932 he began drawing an already established comic strip for the Associated Press, and shortly afterward went to work for Ham Fisher, creator of Joe Palooka.

He credited a hillbilly sequence he had originated for Joe Palooka as being the inspiration for Li'l Abner.

Dissatisfaction with the pay he was receiving from Fisher led Mr. Capp to begin preparing his own strip, which made its debut in eight newspapers in August 1934.

Few doubted that Abner and Dogpatch sprang full-blown from Mr. Capp's feverishly inventive mind. As a teen-ager he had spent some time in the Cumberland Mountain region, but that was the extent of his opportunity to observe mountain life. His strip's hillbilly dialect came from vaudeville shows, Mr. Capp said.

In person, Mr Capp was often as flippantly irreverent as his strip. Asked once why and how he sat every day of the year inside a studio drawing a daily comic strip, Mr Capp replied: "For money, of course."

Showing an adeptness at the aphoristic brevity often required to squeeze thoughts into the confines of comic strip balloons, Mr. Capp once summarized what he saw as his secret of success:

"The public is like a piano," he said. "You just have to know what keys to poke."

Other observers compared his creative and satiric gifts to those of Rabelais, Swift, Dickens and Mark Twain. Among those elevating "Li'l Abner" to the status of literature was John Steinbeck, himself a Nobel Prize winner, who once said he believedMr. Capp's work deserved the same award.

He was married to the former Catherine Wingate Cameron and they had two daughters and a son.