Miguel Lopez, 77, was last seen Tuesday around 8:20 p.m. in the 12800 block of Bromwich Street in Arleta. No one saw him leave his home, authorities said.
A few days before he went missing, Lopez left his home and was found in North Hollywood by a good Samaritan.
The family said Lopez suffers from dementia and has prostate problems, which makes it necessary for him to wear a catheter.
He usually visits businesses at the intersection of Laurel Canyon Boulevard and Osborne Street.
He has gray hair and hazel eyes, authorities said. Lopez stands 5 feet 9 inches, weighs about 143 pounds and was last seen wearing a gray striped long-sleeve shirt, brown slacks and black slippers.
Anyone with more information was urged to call the LAPD Foothill Division at (818) 756-8861. Those wishing to remain anonymous may also call Crime Stoppers at (800) 222-8477.