Roone Arledge, the legendary ABC chairman who masterminded "Monday Night Football," "Nightline," "World News Tonight With Peter Jennings" and other innovations of news and sports programming on television, died of cancer complications yesterday at Memorial Sloan-Kettering Hospital in New York. He was 71.

As president of ABC Sports and then ABC News, Arledge introduced freeze-frames, instant replays, hand-held cameras and sophisticated graphics to sports programs and brought show-business glitz to the coverage of games. The now-standard personalization of athletes in sports broadcasting was another of his innovations. His programming proved a bonanza for ABC.

"Monday Night Football," now in its 33rd season, became television's longest-running, most successful primetime sports series. Another Arledge creation, "ABC's Wide World of Sports," became the most popular sports anthology series in TV history.

Arledge was also the first to insist that sports leagues relinquish the power to approve sports announcers. The prize in that contest was Howard Cosell, an abrasive New York lawyer and local sports announcer who went on to become the voice of American sports.

"Roone Arledge revolutionized television and with it the way people see and understand the world," ABC News President David L. Westin said. "A true creator, Roone invented many of television's most enduring and important programs, all the while fostering the brilliant careers of generations of the most talented men and women to work in front of or behind a television camera.

"His ability to broadcast the essential and unfolding drama in all human situations -- from the gridiron to the world's stage -- transformed not only sports and news but all of us who watched," Westin said.

When Arledge was tapped to head the sagging news division in 1977, some regarded him as simply a showman who might turn the operation into "The Wide World of News." ABC was then rated as the third network. Its audience was less than half that of CBS and NBC.

Arledge proved that he could see the big picture, fix shows and create stars. He lured away key CBS producers and directors and offered CBS's Dan Rather the top news anchor job at ABC. That led to a bidding war that more than doubled Rather's salary, to $2 million a year, and to a new standard of superstar salaries for top news talent.

The ABC news magazines "20/20" and "Prime Time Live" proved to be highly popular, as did a late-night program begun after terrorists seized U.S. hostages in Iran in 1979, "Nightline," with Ted Koppel. It was the first network news program in the late-evening time period and has since won every major award in broadcast journalism.

"20/20," now anchored by Barbara Walters and John Miller, has received more than 200 journalism awards in its 22 years on the air. "PrimeTime Live," with anchors Diane Sawyer, Sam Donaldson and Charles Gibson, became well-regarded for its investigations.

By the end of the 1980s, ABC had become the network to beat in television news, and it held that reputation into the 1990s.

"I took two divisions whose reputations were lower than low -- ABC Sports wasn't even paying its bills, and ABC News was so far behind NBC and CBS they weren't even taken seriously -- and I built them into the best in the world," Arledge said.

In 1990, after he had worked for nearly 30 years to help change the face of television, Arledge was named by Life magazine as one of the 100 most important Americans of the 20th century. In 1994, Sports Illustrated magazine included him among the 40 individuals who had most significantly altered or elevated the world of sports since the 1950s. He was ranked third, behind only Muhammad Ali and Michael Jordan.

But what was said to be Arledge's inattention to some of the more basic details of management eventually led him to be eased out of the news presidency. He was then made chairman. "World News Tonight" had slipped to second place. "Good Morning America" was struggling, and the news division had closed two bureaus and eliminated 50 jobs.

Arledge was succeeded by Westin in 1998.

"I'm proud of the fact that in both sports and news, I took over divisions that were moribund or worse and turned them into the best there was," Arledge said at the time. "In neither case did we go down-market. There was a lot of pressure to do happy talk or go tabloid, and we didn't do that. We became a very serious, important, relevant news organization."

Roone Pinckney Arledge was a native of Long Island, N.Y., and a graduate of Columbia University. He joined ABC Sports in 1960, after five years at NBC. He was named president of ABC Sports in 1968.

From 1964 to 1988, he supervised coverage of 10 Olympic Games, including the 1972 games in Munich disrupted by a terrorist attack. He was credited with taking Olympic cameras beyond the games and into the lives of the athletes, making them compelling characters for viewers.

"We went around the globe and televised sports people never thought of: gymnastics, figure skating, track and field," he said in an interview four years ago. "With close-ups and slow motion, you could see the emotions and expressions. It gave intimacy to the athletes and the events."

For changing the nature of Olympic coverage, he was inducted into the Olympic Hall of Fame.

"I found in sports a combination of drama, grace and beauty, from the heroic highs of winning to the terrible lows of losing," Arledge said. "Certain things were common -- the settings, the people who try to achieve and how difficult that is, the human drama of people. Those elements are always there."

Arledge won three dozen Emmy Awards and nearly every major honor in television, including induction into the Television Academy Hall of Fame, and ABC won nearly 20 Peabody Awards under his leadership. Three months ago, he was given the first Lifetime Achievement Award by the National Academy of Television Arts and Sciences.

In 1995, ABC News became the first network news organization given the Alfred I. duPont-Columbia University Awards' highest honor, the Gold Baton.

Survivors include his wife, Gigi Shaw Arledge, and four children from a previous marriage.

The Associated Press contributed to this report.

Roone Arledge transformed ABC's sports and news coverage.Roone Arledge, at the 1980 Olympics in Lake Placid, N.Y., created such shows as "Monday Night Football," "ABC's Wide World of Sports" and "Nightline."