The fire was reported shortly before noon. The News Journal of Wilmington reports that firefighters saw smoke in a zoo building and found a small fire around a clothes dryer.
The department says firefighters helped zoo staff relocate animals in the affected building, and no people or animals were injured. The fire was placed under control in about a half-hour.
Last month, the zoo was closed temporarily after a large oak tree fell on its monkey house, forcing the evacuation of 24 small monkeys and one bird.
The Brandywine Zoo is Delaware's only zoo and draws about 80,000 visitors a year.
Information from: The News Journal of Wilmington, Del.