Byrom was sentenced to death in 2000 after her son testified at her trial that she had agreed to pay a friend of his $15,000 to carry out the killing. Her trial lawyers never showed the jury admissions her son made in letters to his mother and in a statement to a psychologist that he killed his father out of anger at his abuse.
Edward Byrom Jr. received a short prison term and is now free. Last week, the Supreme Court refused the attorney general's request to set Thursday as the date for his mother's execution.
Mississippi has not executed a woman since 1944 and has never put a white woman to death.
The high court ruled that if Byrom is re-tried the case must be assigned to a different judge.