The category four Sidr Cyclone hit the coast late on Thursday, with winds reaching 240 km (150 miles) per hour, ripping up trees and leveling houses, as well as causing damage to crops, transport routes, communication and power supply lines. Many coastal districts were flooded.
A disaster management official in one of the worst hit areas said, "We have been virtually blacked out all over the country."
The storm has now weakened to a tropical storm and officials are trying to assess the damage and distribute aid to the affected areas. The death toll is expected to rise.
Cyclones kill hundreds of people in Bangladesh annually. However, following devastating cyclones in 1970 and 1991, which claimed half a million and 140,000 lives respectively, the south Asian country introduced a more effective early warning system and built a better network of shelters.