Angelo Dunya Wright (pictured) also admitted to the allegation of personal use of a knife, according to a Sacramento County District Attorney's Office news release.
The plea comes after a mistrial was declared last month, when a Sacramento Superior Court jury voted 11-1 for conviction. The District Attorney's Office had announced that it planned to retry the case.
Prosecutors said Wright and his mother had been estranged for years but had recently reunited.
About an hour before her death, Barber, 42, confided in a friend that she suspected Wright was stealing her jewelry and that she intended to confront him about it. A short time later, Barber was found on her bedroom floor by her father and a neighbor. Authorities said she had suffered numerous stab wounds to her neck and back.
Her dying words to her neighbor, according to prosecutors, were "Help me. My son tried to kill me."
By the time sheriff's deputies and fire personnel arrived the apartment, Barber had died.
Wright fled but turned himself in 36 hours later.
He is to be sentenced to 16 years to life in prison, according to the District Attorney's Office. Sentencing is set for Aug. 27 before Sacramento Superior Court Judge John Winn.