Rescue teams found the body of Vo Van Phoi, 36, who had been working as a scoop truck driver at a dredging project in Tan Uyen City near Ho Chi Minh City.
It was found in the evening after rescuers had searched for more than a day, the police said.
During the heavy downpour on Saturday morning, Phoi and several of his colleagues went to Cai Stream to check if the water could affect their dredging work.
He was swept away in the swollen stream.
Rescue teams mobilized several vehicles, boats and specialized equipment to search for Phoi, but in vain.
The heavy rains on Saturday also hit HCMC and Dong Nai, damaging a number of roads, infrastructure and various construction projects.
Nearly 230 mm of rain fell in HCMC in 90 minutes, the heaviest in the city since 2018.