The children landed at Ramenskoye Airport, near Moscow, on Sunday.
“Twenty-seven Russian children have been repatriated from Baghdad,” a Russian foreign ministry official said.
Thirty other children were sent back to Moscow in late December.
The children’s fathers had been killed during three years of fighting between ISIL and Iraqi troops, the official said.
Anna Kuznetsova, Russia’s envoy for the rights of children, confirmed the arrivals, according to the TASS state news agency.
She said the 27 children were aged from four to 13 and hailed from 10 different regions in Russia.
ISIL seized large swaths of Iraq in a lightning 2014 offensive before the government dislodged the group from urban centres and eventually declared victory in December 2017.
The Kremlin announced in early January that 115 Russian children aged under 10, along with eight aged between 11 and 17, were still in Iraq.
Iraqi law allows detainees to be held with their offspring until the age of three, but older children have to live with relatives.
In November, Kheda Saratova, an adviser to Chechnya’s leader Ramzan Kadyrov, estimated “around 2,000” widows and children of Russian ISIL fighters were still in Iraq and neighbouring Syria.
About 100 women and children, mostly from Caucasus republics, have returned to Russia so far.
Nearly 4,500 Russian citizens went abroad to fight “on the side of terrorists”, Russia’s FSB domestic intelligence agency said last year.
More than 300 people, including 100 foreign women, have been sentenced to death in Iraq for belonging to ISIL, while others have been sentenced to life in prison.