Los Angeles Police Department homicide detectives said the woman, identified as Narda Huerta, was stabbed by her boyfriend after a fight broke out between them at about midnight in a home along the 2800 block of Fairmount Street.
Huerta's two sons wrestled the man to the ground and managed to take the knife away.
Detectives said the sons were also trying to give their mother aid when police arrived. Huerta was taken to County-USC Medical Center, where she was declared dead.
One of the woman's sons was stabbed in the forehead. He was treated at the scene and released.
The suspect was arrested and booked for murder. His identity was not immediately released.
If you have any information regarding this incident, you're urged to contact Los Angeles police at 1 (877) LAPD-24-7.
City News Service contributed to this report.