At least three minors died while 12 others fell sick after having dinner at a madrasa for orphans in the Sadar upazila of Narail early Thursday.
The deceased are Alif, 7, and Imamul Hossain, 13, and Ashraful, 15.
The residents of the Madrasa went to sleep around 10 pm, after having dinner.
A number of minors later complained of food poisoning, said Agdia-Shimulia Jaamiatus Sunnah Mohammadia Kawmi Madrasa administrator Maulana Abdul Kader.
The others were rushed to Narail Sadar hospital as doctors declared Alif and Imamul dead. Another minor Ashraful also collapsed on his way to Khulna Medical College Hospital.
Food poisoning might be the reason, said Sadar hospital physician Anik Saha.