Aziz, 83, was sentenced to life in prison in 1966 but was released in 1985. Also sentenced to life, Islam was released in 1987 and died in 2009.
"These men did not get the justice that they deserved," Vance said in an interview with The New York Times. "What we can do is acknowledge the error, the severity of the error."
The newspaper said that a 22-month investigation conducted jointly by the Manhattan district attorney's office and lawyers for the two men found that prosecutors, the FBI and the New York Police Department withheld evidence that would likely have led to the acquittal of the two men.
A third man, Mujahid Abdul Halim, 80, confessed to Malcolm X's murder and was released from prison in 2010. Halim claimed during their 1966 trial that Aziz and Islam were innocent.
All three were members of the Black nationalist group Nation of Islam, which Malcolm X had recently renounced.
Malcolm X was shot dead by three gunmen on February 21, 1965 as he prepared to deliver a speech in a Manhattan ballroom.
Halim was taken into custody at the scene with a bullet wound to the leg.
Aziz and Islam were arrested several days later. Both denied involvement in the assassination and provided alibis for where they were at the time of the shooting.
Aziz said in a statement Wednesday that "the events that brought us here should never have occurred; those events were and are the result of a process that was corrupt to its core -- one that is all too familiar -- even in 2021."
"While I do not need a court, prosecutors, or a piece of paper to tell me I am innocent, I am glad that my family, my friends, and the attorneys who have worked and supported me all these years are finally seeing the truth we have all known, officially recognized," he added.
According to the Manhattan district attorney's office, Thursday's press conference will also be attended by civil rights attorney David Shanies and Barry Scheck, co-director of the Innocence Project.
Shanies and the Innocence Project, a nonprofit which has secured the exoneration of hundreds of wrongfully convicted prisoners in the United States, collaborated with Vance's office in re-investigating the case.
The review of the case followed the release of a Netflix docuseries "Who Killed Malcolm X?"
The Times said the re-investigation did not identify "who prosecutors now believe really killed Malcolm X, and those who were previously implicated but never arrested are dead."
"Nor did it uncover a police or government conspiracy to murder him," the newspaper said. "It also left unanswered questions about how and why the police and the federal government failed to prevent the assassination."
Considered one of the most influential African Americans of the 20th century along with Martin Luther King Jr, Malcolm X was an outspoken advocate of Black rights.
Born Malcolm Little in 1925, he fell into petty crime as a young man and became a devout follower of Islam while in prison.
Upon his release, he changed his surname to "X" as a symbol of the original name of his family lost under slavery.
He rose to prominence as a minister and spokesman for the Nation of Islam, advocating Black self-dependence and esteem. He also did not shy away from the use of violence for self-protection.
Disillusioned with the Nation of Islam, Malcolm X broke away from the group in 1964 and formed the short-lived Organization of Afro-American Unity to continue the promotion of Black rights.