At least 23 people in central Vietnam died on Tuesday as the typhoon struck the coast. The storm killed at least 240 people in the Philippines when it hit.
Ketsana, which made landfall Tuesday afternoon local time, battered Quang Nam province with winds up to 144 km/h.
The Vietnam deaths occurred in six provinces, with many being caused by falling trees and electrical lines, officials said.
More than 170,000 people were evacuated from Vietnam’s central coast as the storm approached, said disaster official Nguyen Van Vy.
Rains and heavy winds have knocked out electricity in the central provinces.
"There's a blackout across our entire province," said Truong Ngoc Nhi, vice-governor of Quang Ngai province, south of Danang. "Many streets are strewn with fallen trees and utility poles. It looks like a battlefield."
Vietnam Airlines has cancelled all flights to the tourist destinations of Danang and Hue.
Philippine relief efforts continue
Aid agencies began mobilizing relief supplies to help people in the Philippines in the aftermath of Ketsana, which dumped more than a month's worth of rain on the Philippines in less than 24 hours, causing massive flooding.
Rescuers in the Philippines were continuing to search for bodies in the swollen rivers on Tuesday.
The National Disaster Co-ordinating Council said the homes of almost 1.9 million people were inundated by flood waters, with nearly 380,000 people brought to schools, churches and other evacuation centres.
Officials in the Philippines are calling for more international aid as two more storms brew just east of the island nation in the Pacific.
"We are trying our level best to provide basic necessities, but the potential for a more serious situation is there," said Defence...