The stabbing occurred during an argument between the men at the Town and Country Village, located at 855 El Camino Real, police Lt. Sandra Brown said.
Aaron Womack, a 21-year-old East Palo Alto resident, called 911 at about 8 p.m. and said he had stabbed his stepfather, Brown said.
Officers arrived and found the man suffering from wounds to his neck and chest. He was transported to Stanford Hospital where he underwent surgery and is now doing well, Brown said.
Police believe the weapon used was a 4-inch knife.
Brown said she did not know what the argument was about.
Womack was booked into Santa Clara County's main jail for attempted murder.