The child was found outside The Woods Apartments complex, off Snell Avenue. The apartment complex is a large building, with more than 1,800 units.
Police said the child had no adult supervision and was only wearing a diaper.
A woman called security about something small she found at around 3 a.m. "I saw a baby and she was like, I just found him over here," security guard Mohammed Shaheed said. "He was really dirty, and muddy."
Guardian of 2-year-old boy found wandering alone in San Jose located
Shaheed said he and the woman checked nearby apartment doors to see if they were open in an effort to find the child's parents.
Paramedics soon arrived and took care of the 2-year-old boy. "He wasn't worried about anything, but he was calling for his mom and dad that was the only thing he was saying in Spanish, that's it," Shaheed said.
Police said the boy was checked out at the hospital and turned over to the Department of Family and Child Services.
Police are interviewing the guardian to see what the next steps will be.