Tom Keeton, 30, and his 5-year-old stepson, Robert Devin Taylor, died a short time later at separate hospitals, said Champaign County Deputy Coroner Joseph Ward.
Keeton's 13-year-old stepdaughter, Kaelin Taylor, died in the afternoon, said Champaign County Chief Deputy Coroner Bill Fabian.
Autopsies were scheduled for Saturday.
The children's mother, Amy Keeton, was treated and released from Carle Foundation Hospital in Urbana, said nursing supervisor Lynn Clarkson. Her age was unavailable.
Crews fought the fire in southwest Champaign for almost two hours. A neighboring house caught fire, but had little damage, fire officials said. The first home was a total loss.
Officials were investigating the cause of the fire.
