The soldiers had just arrived in the former French colony to join a UN peace-keeping mission and were travelling south from the capital Yamoussoukro to the main city Abidjan when their canvas-covered lorry overturned on Friday evening.
"They had just arrived the same day and they were travelling to where they had been posted in Abidjan," Colonel Omar El Khadir, the UN military spokesman, told Reuters.
"(The lorry) rolled over ... We don't know what the cause of the accident was. An inquiry is underway," he said.
Four were killed instantly and two more died in hospital, he added.
The French peace-keeping force which backs up the UN troops transported the injured from the scene by helicopter. One soldier remained in a critical state, El Khadir said.
Army sources in Bangladesh earlier said that 12 people had been injured, but El Khadir said the number of injured was 11.
Bangladesh has nearly 3,000 soldiers with the UN peace-keeping mission in Ivory Coast, split in two since rebels seized its northern half following a failed attempt to oust Laurent Gbagbo, the president, in September 2002.
Overall, around 10,000 Bangladeshis have been working in 12 UN missions worldwide, the Bangladeshi army said.
Ivory Coast's road network has deteriorated considerably due to lack of maintenance since hostilities broke out. Main routes are peppered with huge potholes and local vehicles are often poorly maintained, meaning accidents are frequent.