Two police officers tried to rescue the pair after they spotted the blaze in Seacombe at about 20:30 GMT, but the heat and smoke was too intense.
The woman was later rescued from the house in James Street but died later in hospital while a man's body was discovered inside the property.
Merseyside Fire and Rescue Service is investigating the cause of the blaze.
The service's area manager Dave Mottram said: "Police officers made valiant attempts to save the occupiers, forcing entry through the front door, but unfortunately they were unable to do so due to the effects of severe heat and smoke.
"Firefighters were quickly on scene and made entry into the property wearing breathing apparatus, where they found the ground floor was well alight."
He said they tackled the fire and stopped it spreading to neighbouring properties and had put it out by 21:30.
A man and woman, believed to be in their 80s, have died after a fire at a house in Wirral on Friday night.