Tiffin Police Department officials said they received a call at about 7:45 a .m. that the home was on fire at Highland Trailer Park.
Tiffin Fire and Bascom Fire officials pulled the adult male and five children from the home. They were transferred to Tiffin Mercy Hospital where all six were declared dead, the Toledo Blade reported.
The children were identified as the son of the adult male and the four daughters of the man's girlfriend, who was at work at the time of the fire.
The names of the six dead were not reported.
Tiffin Fire and the State Fire Marshal's Office are investigating the cause of the fire.