But his widow, Dee Jenkins, disagreed with Twitty's children, who are from a previous marriage. They fought a 14-year legal battle over his estate after his death, which the children eventually lost.
She said Friday that the family knew what they signed 18 years ago and that their lawsuit has dishonored their father's memory.
But his daughter, Joni Jenkins Riels, said that nothing was explained and that they didn't know what rights they were giving up.
"Dad had a long relationship with Sony. We tried to work with them, but it didn't work out. So, we had to file the lawsuit," Riels said Friday.
The children could get more than $100,000 a year from the recordings if they were to get the copyrights back, says Rose Palermo, a lawyer for his estate, who added that she was concerned about the claims in the lawsuit.
"I'm somewhat astounded that they make an allegation that they didn't know what they were doing," Palermo said. "He (Twitty) was supporting his children. And at the time, he was giving some of them $50,000 a year in salaries and a free place to live.
"To make this allegation is a direct slam at Conway, who was one of the most honorable and decent guys that I've known in the music business," she said.
Duff Berschback, representing Sony/ATV, declined to comment, saying he hadn't reviewed the lawsuit.
Twitty, whose real name was Harold Jenkins, died after a 30-year career with 40 No. 1 hits, including "Hello Darlin"' and "Louisiana Woman, Mississippi Man," a duet with Loretta Lynn.
