Cashier Marilyn Howard suffered four bite wounds on her arms and head and scratches on her face during the frightening incident at the Home Depot location in Okeechobee.
The spider monkey's name is Spanky and her owner, Tina Ballard, has a history of taking the animal wherever she goes, including shopping excursions.
A YouTube video shows Spanky in a shopping cart being pushed through the aisles of a Lowes store.
But on the trip to Home Depot, Spanky was apparently upset about being left in the SUV. Somehow, she escaped and ended up inside the store, where she took a bite out of a cashier who was on a break.
"I was looking for another associate to go to the service desk and announce that 'your monkey is loose,'" Howard told Inside Edition. "I never thought I would say that."
Howard refused medical treatment but told deputies she would go to a hospital to be evaluated.
Animal Control and Florida Fish and Wildlife Conservation Commission were notified about the incident and are continuing their investigation into the attack.