The incident happened on Tuesday at the Cabarceno Natural Park in northern Spain, in the Cantabria region.
Joaquin Gutierrez, 44, was cleaning out the elephant stables when a female elephant swatted him aside with its trunk, zoo officials said. The elephant knocked the man into the bars of the enclosure, where he struck his head.
He was taken to hospital after the incident and died several hours later.
The 4,000-kilogram African elephant was with her calf at the time of the attack, authorities said. She also had a foot infection and was likely pregnant.
“We’re talking about unpredictable animals,” said Javier Lopez Marcano, the tourism minister for Cantabria, which owns the zoo.
“The force of the strike was tremendous, of a magnitude that one could not survive,” Marcano said in a statement.
Zoo officials say Gutierrez had been working at the zoo for nearly 20 years.
Marcano suggested that the accident was due to a lack of caution.
It was the first elephant-related death in the park’s 31-year history.
Police and tourism officials are investigating the incident.
— with files from The Associated Press