The child was with family members at the party at a home in the 3200 block of Malabar Street Saturday night. Around 11 p.m., the family realized the little girl had disappeared and called police.
A nearly three-hour search was conducted in the neighborhood. The girl was found with the suspect in a shed behind a nearby residence around 2 a.m.
The girl was examined at a hospital. She was not harmed, police said.
The man who hosted the baby shower said around 40 people attended the party.
"Somehow their investigation revealed the child was lured away by a male that had attended the party," said Los Angeles police Sgt. Gabriel Lara.
The suspect, who authorities identified as 55-year-old Edward Lopez, was taken from the scene in an ambulance. He was later booked into the Metropolitan Detention Center on a charge of kidnapping for the purpose of committing a sexual offense.
The girl has been returned to her family.