The body of Caroline Jessett, 50, was found by police at her house on Cowley Road in Littlemore, Oxfordshire on November 21.
Yet after searching the home a week later, officers found the body of her mother in the downstairs bathroom.
The inquest heard how the corpse of Pauline Jessett, 78, was discovered in the bath covered with blankets and sheets.
It is believed she had died in March 2012 and her daughter was not able to cope with her death so kept the body in their home.
Coroner Darren Salter deemed Miss Jessett had died some time in 2013 but was unsure when.
Next door neighbour Raymond Bailey, who has lived on the street for 30 years, described the women as reclusive and believed there was no suspicion to think anything was wrong.
He said last year: "There were no dustbins left out, no papers, no milk bottles.
"We never used to see them. They wouldn't have opened the door to anybody."
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Detectives were forced to hold back on their investigation after environmental health officers declared the house structurally unsound.
Police described Miss Jessett's body as 'mummified' and said she could only be identified from a unique serial number on her artificial hip.
Officers later confirmed the deaths were not being treated as suspicious.
Post-mortem examinations carried out on both bodies came back inconclusive.
The coroner described the case as "sad and unusual", recording a verdict of death by natural causes for natural causes for Caroline Jessett.
He recorded an open verdict for Pauline Jessett, claiming it was impossible to determine a cause of death.