His family released a statement saying Goldwater died of natural causes at his home in the Phoenix suburb of Paradise Valley.
"He was in his own bed, in his own room, as he wished, overlooking the valley he loved, with family at his side," the statement said. "He died as he lived: with dignity, courage, and humility."
Goldwater was the 1964 Republican nominee for the U.S. presidency. He ran unsuccessfully against President Lyndon Johnson with a platform that contained the rallying cry, "Extremism in the defense of liberty is no vice. Moderation in the pursuit of justice is no virtue."
Although Johnson beat him in a landslide, Goldwater became a symbol of American conservatism.
He has been credited as a founder of the modern conservative movement and with contributing to Ronald Reagan's rise to prominence and the presidency.
"He was truly an American original. I never knew anyone quite like him," President Clinton said Friday. He called Goldwater "a great patriot and a truly fine human being."
Goldwater was a tough-talking westerner who prided himself on telling the truth. Although he originally supported Richard M. Nixon in the 1960 elections, he later called him "the world's biggest liar." In 1974 Goldwater told Nixon that he faced imminent impeachment because of the Watergate scandal. Nixon subsequently resigned.
Goldwater was labeled "Mr. Conservative," and The New York Times reported that, in recent years, a distance had grown between Goldwater and some supporters. Some political observers traced that estrangement to some of Goldwater's statements on such social issues as his support for abortion rights and support for homosexuals serving in the military.
"You don't need to be 'straight' to fight and die for your country," he said. "You just need to shoot straight."
Goldwater was born in Phoenix on Jan. 1, 1909 to Baron and Josephine Williams Goldwater. In 1928, he attended Staunton Military Academy in Virginia.
He joined the army in 1930, and married his first wife, Margaret "Peggy" Johnson four years later. In 1937, Goldwater became the president of his family's business - the Goldwater department store chain.
He served in World War II as an pilot and colonel in the U.S. Army Air Corps. In 1945, Goldwater became major general and chief of the Arizona Air National Guard.
His political career was sparked in 1949 when he helped gather Phoenix City Council candidates who targeted the area's widespread prostitution and gambling.
He was first elected to the Senate in 1952, defeating then-Senate Majority Leader Ernest McFarland. He served in the Senate for 30 years, giving up his seat in 1964 to run for president, but he was re-elected to the Senate in 1968.
Goldwater's nomination to the presidency came after a rough conventiofight with New York Gov. Nelson Rockefeller. After his nomination, he galvanized the remaining delegates, including Rockefeller, with a controversial speech.
"Extremism in the defense of liberty is no viceÂ…Moderation in the pursuit of justice is no virtue," Goldwater declared.
That comment, and Goldwater's pro-military views on Vietnam, were seized upon by Democrats, who portrayed him as a warmonger and a possible destroyer of Social Security.
He lost the presidency to incumbent Lyndon B. Johnson, who, as vice president, had succeeded John F. Kennedy following his assassination.
In 1985, Goldwater's wife, Peggy, died. Goldwater retired two years later after serving five terms in the Senate. He surprised friends and colleagues when he remarried at the age of 83 to a 51-year-old Susan Schaffer Wechsler in 1992.
U.S. Rep. John Shadegg of Arizona commented about Goldwater in The New York Times last year: "His single hallmark is that people don't necessarily agree with what he believes in. He doesn't sugarcoat it. He has the guts to tell it like it really is. That's never going to change. It wouldn't be Barry Goldwater if it did."
Goldwater had been in declining health for months. In 1996, he suffered a stroke that damaged the frontal lobe of his brain, which controls memory and personality. He also suffered from Alzheimer's disease.
Goldwater is survived by his wife, Susan, and his children from his first marriage.
Visitation was scheduled for all day Tuesday and Wednesday morning at Trinity Cathedral in Phoenix. Goldwater's funeral will be Wednesday afternoon at Grady Gammage Auditorium on the Arizona State University Campus in suburban Tempe.