NEW YORK - Odetta, the folksinger with the powerful voice who moved audiences and influenced fellow musicians for a half-century, has died at 77.

She died Tuesday of heart disease at Lenox Hill Hospital, said her manager of 12 years, Doug Yeager. She was admitted to the hospital with kidney failure about three weeks ago, he said.

In spite of failing health that placed her in a wheelchair, Odetta performed 60 concerts in the last two years, singing for 90 minutes at a time. Her singing ability never diminished, Yeager said.

"The power would just come out of her like people wouldn't believe," he said.

With her booming, classically trained voice and spare guitar, Odetta gave life to songs of workingmen and slaves, farmers and miners, housewives and washerwomen, blacks and whites.

First coming to prominence in the 1950s, she influenced Harry Belafonte, Bob Dylan, Joan Baez and other singers with roots in the folk boom.

With an Odetta record on the turntable, listeners could imagine spirituals and blues as they rang out from a weathered back porch or around a campfire a century before.

"What distinguished her from the start was the meticulous care with which she tried to re-create the feeling of her folk songs; to understand the emotions of a convict in a convict ditty, she once tried breaking up rocks with a sledgehammer," Time magazine wrote in 1960. "She is a keening Irishwoman in 'Foggy Dew,' a chain-gang convict in 'Take This Hammer,' a deserted lover in 'Lass From the Low Country.' "

Odetta called on fellow blacks to "take pride in the history of the American Negro" and was active in the civil-rights movement. When she sang at the March on Washington in August 1963, "Odetta's great, full-throated voice carried almost to Capitol Hill," the New York Times wrote.

She was nominated for a 1963 Grammy for best folk recording for Odetta Sings Folk Songs. Two more Grammy nominations came in recent years, for her 1999 Blues Everywhere I Go and her 2005 album Gonna Let It Shine.

In 1999, she was honored with a National Medal of Arts. President Bill Clinton said her career showed "us all that songs have the power to change the heart and change the world."

"I'm not a real folksinger," she told the Washington Post in 1983. "I don't mind people calling me that, but I'm a musical historian. I'm a city kid who has admired an area and who got into it. I've been fortunate. With folk music, I can do my teaching and preaching, my propagandizing."

Among her notable early works were her 1956 album Odetta Sings Ballads and Blues, which included such songs as "Muleskinner Blues" and "Jack O' Diamonds"; and her 1957 At the Gate of Horn, which featured the popular spiritual "He's Got the Whole World in His Hands."

She continued to record in recent years; her 2001 album Looking for a Home (Thanks to Leadbelly) paid tribute to the great blues singer, to whom she was sometimes compared.

Odetta's last big concert was Oct. 4 at San Francisco's Golden Gate Park, where she performed in front of tens of thousands at the Hardly Strictly Bluegrass festival, Yeager said. She also performed Oct. 25 and 26 in Toronto.

Born Odetta Holmes in Birmingham, Ala., in 1930, she moved with her family to Los Angeles at age 6. Her father died when she was young and she took her stepfather's last name, Felious. Hearing her in glee club, a junior high teacher made sure she got music lessons, but Odetta became interested in folk music in her late teens and turned away from classical studies.

She got much of her early experience at the Turnabout Theatre in Los Angeles, where she sang and played occasional stage roles in the early 1950s.

She picked up occasional acting roles in TV and film. None other than famed Hollywood columnist Hedda Hopper reported in 1961 that she "comes through beautifully" in the film Sanctuary.

In the Washington Post interview, Odetta theorized that humans developed music and dance because of fear, "fear of God, fear that the sun would not come back, many things. I think it developed as a way of worship or to appease something. . . . The world hasn't improved, and so there's always something to sing about."

Odetta is survived by a daughter, Michelle Esrick of New York, and a son, Boots Jaffre, of Fort Collins, Colo. She was divorced about 40 years ago and never remarried, her manager said.

A memorial service was planned for next month, Yeager said.

Associated Press writer Cristian Salazar contributed to this report.