A suicide bomber detonated an explosives-rigged minibus in a crowded shopping area in Baghdad's Karrada district early on July 3, sparking infernos in nearby buildings that burned many victims alive.
"One hundred and fifteen martyrs were identified directly after the bombing by their families," health minister Adila Hamoud told a televised news conference.
But the identity of 208 more people killed in the blast, many of whose bodies were burned beyond recognition, could not be determined, and they were sent for DNA testing, Hamoud said.
People have been furious over delays in determining the fate of their loved ones, and have sharply criticised the Iraqi government for failing to protect them.
IS overran large areas north and west of Baghdad in 2014, but Iraqi forces have since regained significant territory from the jihadists.
The extremists have responded to battlefield setbacks by striking back against civilians, and experts have warned there may be more bombings as the jihadists continue to lose ground.