Officials said Kali, a 12-year-old Goeldi monkey, was stolen when someone broke into the Palm Beach Zoo.
They believe she is in danger.
Kali was last seen when the zoo closed around 6 p.m. on Sunday.
The Goeldi monkey species is popular on the illegal pet trade and can be valued at over $10,000.
Kali weighs one pound and has anti-inflammatory issues, is on a special diet and needs medication.
The zoo is looking to offer a reward for the safe return of the monkey.
Anyone with information is asked to contact the West Palm Beach Police Department.