The boy was found in the 1700 block of Northwest 152nd Street about 1 p.m.
"The child just got out of the house, and it's unfortunate that we don't know how he got out," said Miami Gardens Police Det. Mike Wright.
The boy was then taken the Miami Gardens Police Department headquarters, where he waited until his mother arrived.
"She came in willingly and she offered her apologies," said Wright. "We're just excited the mother is back with her child."
The boy's mother told police and investigators with the Department of Children and Families that she went to work and left her son at home with another adult. The boy's mother said she didn't tell the babysitter, who was asleep, that she was leaving.
"Our investigation reveals the child is very active, and she claims she locked the door; however, that's inconclusive," said Wright.
No charges have been filed.