An 84-year-old woman woke up in a morgue shortly after being declared dead, the Daily Telegraph reported.
Doctors became aware of the error when someone saw her body bag moving.
The woman, from the village of Jablonowo in central Poland, was pronounced dead by a doctor from the emergency medical services after her husband called an ambulance.
"A funeral company took the body to the morgue,” a police spokesman told the Telegraph. "Several hours later, a worker there noticed the bag containing the body was moving. He called a doctor, who noted the woman's vital functions had returned."
The woman was taken to a nearby hospital where she was said to be in a serious condition.