The deceased were identified as Khoka Mila, 60, of Kazipur upazila in Sirajganj district and Mohammad Ali, 70 of Patiau pazila in Chattogram district.
Illias Hossain, a caretaker of the Ijtema ground, said Khoka Mia died around 10:30 pm while Ali around 1 am due to old age complications at their respective tents.
With this, a total of three devotees died at the Ijtema venue.
Earlier on Thursday morning, Yeakub Ali, 85, son of Hashem Ali of Kotalipara in Gopalganj, died just after arriving at the Ijtema venue.
The first phase of Biswa Ijtema, the second largest congregation of Muslims after Hajj, began on the banks of the Turag River in Tongi after Fazr prayers on Friday.
The Ijtema began with "a'mbayan" (general sermons) by Pakistani Islamic scholar MaulanaObaidulKhorshed.
Several thousand devotees are expected to offer Jum'a prayers on the first day of the Ijtema.