Dr Chowdhury Sajjadul Karim, nuclear physicist and former advisor to caretaker government, passed away on Friday night at the age of 67.
He was the former Bangladesh Atomic Energy Commission chairman.
He died at a hospital in Dhaka at 10:40pm on Friday.
His son Shabab Karim said he had suffered from pneumonia for a week.
The former Bangladesh Physical Society president was an international nuclear inspector for the Vienna-based global watchdog, International Atomic Energy Agency.
He advised the Fakhruddin Ahmed-led caretaker government on agriculture issues.
Dr Karim, an expert on nuclear power and energy, had also served on national committees formulating energy and power policies.
He co-authored the national energy policy in the 1990s.