J. Willard Marriott, a poor Utah sheep farmer's son who borrowed money to open a root beer parlor in Washington more than 50 years ago and saw the business grow into a billion-dollar international hotel, restaurant and food service conglomerate, died of heart failure last night at a hospital in Wolfeboro, N.H. He was 84.

Mr. Marriott's son, Richard, said his father had been vacationing at his summer home in Mirror Lake when he was stricken about 9 p.m. "It was sudden," the son said. "We took him to the hospital and he died shortly after his arrival."

Mr. Marriott was chairman and founder of the Marriott Corp., which operates a worldwide network of more than 125 hotels, 2,500 fast food restaurants, airport gift shops, airline flight kitchens and specialty restaurants, and runs catering operations for businesses, health care facilities and colleges.

With $1,500 in borrowed money and $1,000 in savings, Mr. Marriott bought an exclusive root beer franchise and came east from Utah in 1927 to sell his product, banking on the belief that in the sultry, sticky summers of a pre-air-conditioned Washington, root beer would be a popular drink.

With his wife, Alice, he opened his business at 14th Street and Park Road NW in a shop with sawdust on the floors and nine stools at the counter.

When the weather turned cool that fall they borrowed recipes from the chef at the Mexican Embassy nearby and began selling chile, barbecue and hot tamales, foods that were popular in Mr. Marriott's native West. He called his place the "Hot Shoppe."

Five years later there were seven Hot Shoppes in the Washington area, and although many restaurants failed during the Depression of the 1930s, Mr. Marriott's Hot Shoppes grew steadily. In 1937, he noticed airplane passengers at National Airport carrying food on board from a nearby Hot Shoppe, and he began catering meals for airlines. He opened his first motor hotel, the Twin Bridges Marriott, on the Virginia side of the 14th Street bridge between Rte. 1 and the George Washington Parkway in 1957.

In 1964 Mr. Marriott turned the presidency of the company over to his son, J. Willard Jr., who took charge of day-to-day operations and has since become the driving force in the business. At the time annual sales were $87.4 million and there were 122 Marriott outlets in the District of Columbia and 14 states. Mr. Marriott became chairman of the board but has remained mainly in the background during the company's unprecedented growth and expansion over the last 20 years.

A lifelong Republican and long one of the party's financial mainstays, Mr. Marriott became a close friend of President Nixon when Nixon was a young congressman newly arrived in Washington, and he served as chairman of the Nixon inaugural committees in 1969 and 1973. He also gave Nixon's brother, Donald, a job with the company scouting sites for potential Marriott hotels.

Initially in 1968, Mr. Marriott had supported the presidential candidacy of former Michigan governor George Romney, a boyhood friend and a devout Mormon like Mr. Marriott. He transferred his backing to Nixon when Romney withdrew.

In 1970, Mr. Marriott was a principal organizer of the massive "Honor America Day" celebration held on the Washington Monument grounds on the Fourth of July. At a time when the nation was deeply divided over U.S. involvement in the war in Vietnam, that observance was intended as a demonstration of American patriotism, and it included an entertainment program with Bob Hope as the master of ceremonies and an interfaith religious service led by the Rev. Billy Graham.

Backed originally by such organizations as the American Legion and the Boy Scouts, Honor America Day eventually drew support from such congressional antiwar liberals as then-senators George McGovern of South Dakota and Edmund Muskie of Maine. But it also attracted youthful antiwar protesters who staged a counterdemonstration. Nevertheless, Mr. Marriott termed the event, which drew 450,000 to the Monument Grounds, "the greatest thing we have had in Washington in a long time."

As a Mormon, Mr. Marriott personally eschewed alcohol, tobacco, coffee and tea -- although all four were served in his hotels -- and he contributed one-tenth of his before-tax earnings to the church. He once said that serving liquor in his hotels was essential to staying in business.

A tall, slim westerner, Mr. Marriott had a wry smile and spoke with a drawl that sometimes evoked the memory of Will Rogers. He was born Sept. 17, 1900, near Ogden, Utah, in the small Mormon settlement of Marriott, which was named for his grandfather, John Marriott, a man with five wives who had participated in the great migration of Mormon pioneers to Utah in 1847.

As a youth, Mr. Marriott learned to tend sheep during the heat of the Utah summers and the bitter cold winters from the Basque shepherds who worked for his father. When he was 14 he made his first business deal when his father sent him by rail to San Francisco with a flock of sheep to sell. The next year his father sent him to Omaha with more sheep to sell.

When he was 18 he began the missionary service obligatory to all young Mormons, and he spent the next two years in New England seeking converts to his faith. He returned to Utah to find the price of sheep had dropped precipitately -- from $14 to $3 a head -- and his father along with most other Utah sheep ranchers had gone bankrupt.

Mr. Marriott spent the next six years working his way through Weber State College in Ogden and then the University of Utah, where he graduated in 1926. He sold clothes to fellow students, managed a bookstore, taught high school English and sold woolen underwear to loggers from California.

Weber College gave him a job as an English teacher, college treasurer and theater manager in 1926, but Mr. Marriott wanted bigger challenges, and he took a chance on the Washington area franchise for A&W root beer, a new product developed by two westerners named Allen and Wright.

He came east in the spring of 1927 to get his business started, then flew back to Salt Lake City to marry his college sweetheart, Alice Sheets, in the Mormon Temple. On the morning of his wedding, Mr. Marriott recalled, he got up early to try to collect some money that a woolen company still owed him as his commission on sales the previous year, and he was two hours late for the ceremony, but his worried bride was still waiting.

Instead of a reception, Mr. Marriott's mother-in-law gave the couple $200 as a wedding gift, and they took the money, pooled it with their remaining savings and borrowings and drove to Washington in Mr. Marriott's Model-T Ford to seek their fortune.

"No person can get very far in this life on 40 hours a week," Mr. Marriott once said, and he applied that maxim with diligence during the early years of his business. He worked 15 to 18 hours a day, tried a variety of promotional tactics, including handing out free root beer coupons on street corners, and his business soon prospered.

His health did not. In 1933, Mr. Marriott collapsed from what was diagnosed as a disease of the lymphatic system, and he was told by his doctors that he had only two years to live. He spent six months hunting, fishing and riding in Maine and Florida, then returned to work.

His health was restored, but Mr. Marriott decided to ease his workload, and he built up a management team that eventually came to include his three brothers and, when they grew older, his sons, J. Willard Jr. and Richard.

Except for the war years, when gasoline rationing reduced his customers' mobility, Mr. Marriott's business grew dramatically. His Hot Shoppes eventually yielded to the likes of Marriott's Roy Rogers Family Restaurants, Bob's Big Boy Coffee Shops, Junior Hot Shoppes and Farrell's Ice Cream Parlour restaurants, and in recent years the hotel division has accounted for an ever-increasing share of the Marriott business.

A man of deep religious convictions who always said grace before each meal, Mr. Marriott was president of the Washington Stake of the Church of Jesus Christ of Latter-day Saints from 1948 to 1957. He was a benefactor of both the University of Utah, where the Marriott Library is named for him, and Brigham Young University, where he donated funds for the Marriott Activities Center.

He was a former director of the Riggs National Bank, the Washington Board of Trade, the Chesapeake & Potomac Telephone Co., American Motors and the National Association of Manufacturers.

Although a millionaire many times over who no longer needed the money, Mr. Marriott always stayed close to his business, even after turning the reins over to his son. "All my life, I've been frightened to death that I would go broke like my father did," he said. "I never forgot that something could happen to your business."

Besides his wife and sons, survirivors include eight grandchildren and four great-grandchildren.