Twitty, who had more than 50 number one hits in the country music charts, collapsed last night on his tour bus following a performance in nearby Branson, Missouri.
The hospital said his family was with him when he died, but would not reveal the cause of death.
A year ago, Twitty collapsed on stage during a matinee performance in Branson. He said at the time that he fainted because he 'simply got too warm', and dismissed remarks by the theatre manager that he was suffering from diabetes.
Twitty was born Harold Jenkins in Mississippi and raised in Helena, Arkansas. He took his name from two small towns - Conway from Conway, Arkansas, and Twitty from Twitty, Texas.
In the Fifties, he started out as a rock'n'roll singer and his song, 'Lonely Blue Boy', went gold. His first number one country hit was released in 1958 - the ballad 'It's Only Make Believe'. He specialised in ballads of lost love and his biggest hits included 'Tight Fittin' Jeans', 'Hello Darlin' ' and 'After All The Good is Gone'. In the Seventies, he sang a string of hit duets with Loretta Lynn. Twitty was prolific, releasing an average of one album every eight months.
'I pick a song a woman will like for sure,' he once said. 'Women are more sensitive and get the point quicker. I like a song that says things a man wants to say and doesn't know how to say.' Another veteran country singer, Porter Wagoner, described him as a legend. 'We got into the music business about the same time,' he said. 'I first met him when I was playing a club in Minneapolis in 1957. He had a pop song which was a pretty big hit at the time, but he told me he wanted to be a country singer and recording star. He became one of the true legends of our business.
'He had a great ear for songs that were commercial. He'd go through hundreds of songs, looking for a single or numbers for an album.'
Twitty had a strong interest in sport and before he went into show business, was offered a contract with the professional baseball team, the Philadelphia Phillies. Later, he became part owner of the minor league baseball team, the Nashville Sounds.
Twitty once summed up his career: 'I've survived and stayed on top. I worked my way up there and stayed there and I did it without taking dope.'