The animals were discovered on Friday in Pandamasue Forest, located between Hwange National Park and Victoria Falls, the country’s parks authorities said.
Blood samples have been taken to a laboratory for analysis to determine their cause of death, a spokesman for the Zimbabwe National Parks and Wildlife Management Authority, said on Sunday.
The dead elephants were found with their tusks still intact, ruling out poaching.
In recent years poachers in Zimbabwe have poisoned dozens of elephants in order to sell their ivory tusks to illegal traders.
“Only elephants were affected, no vultures or any other animals were affected,” parks spokesman Tinashe Farawo told reporters.
“Initial tests show that it is not cyanide. We are also ruling out poachers because the tusks were intact.”
Scientists are still investigating the deaths in the country’s Okavango Delta area, with poaching, poisoning and anthrax all ruled out.
Botswana has the world’s largest elephant population, estimated at 156,000. Zimbabwe has the second largest – with an estimated 85,000.
Last year about 200 elephants in Zimbabwe died of starvation as a result of the country’s drought.