The blaze, at a semi-detached council house in Grange Road, Farnborough, Hampshire, the home of Julie Cole and her family, is thought to have started in a bedroom.
Two police officers tried to rescue the children - a six-year-old girl, a boy aged five and two four-year-old boys - but were driven back by smoke. The dead man was named unofficially as former postman Alan Lovegrove.
Two of the dead children were said to be Christopher Cole, aged four, and his five-year-old brother, Dominic, from Mrs Cole's third marriage. The other victims were named as Jamie Cavanagh, four, and his sister Hayley, six, who were staying overnight.
Mrs Cole escaped the burning house through the back door with 13-year- old son Kenneth and daughter Stacey, aged eight.
Another daughter, 11-year-old Sarah, is in intensive care at nearby Frimley Park Hospital.
Neighbour Vicky Dawson, 14, said she heard Mrs Cole calling for help. She said: "Julie was saying 'My babies are in there, my babies are in there'.
"Sarah was at the window with her face all black, screaming for help. It was terrible."
Pc Richard Goddard and Wpc Lisa Graham tried to get to the trapped children. Pc Goddard crawled on his hands and knees up the stairs.
A neighbour, who declined to be named, said: "Young Vicky raised the alarm and I tried to go into the house, but just then a police car came up and a policeman went through that smoke on his hands and knees.
"That man deserves a medal and so does the Wpc. They went straight in. You couldn't see anything. The smoke was coming through the roof tiles so thickly you couldn't see the roof."
Police said the mother and two children who escaped the fire were being released from hospital.Reuse content