Debbie Reynolds died of a stroke and her daughter Carrie Fisher's cause of death was cardiac arrest, their death certificates have confirmed.
The Los Angeles County Department of Public Health's death certificate for Debbie has "intracerebral haemorrhage" as the cause of death, which is a type of stroke caused by bleeding in the brain rather than the more common type caused by a clot.
The certificate lists high blood pressure as an underlying cause.
Debbie died aged 84 on December 28 at Cedars-Sinai Medical Centre, the certificate says.
It lists Debbie's son Todd Fisher as the notifying party, and says the actress had been in the entertainment business for 68 years.
Debbie fell ill while making memorial plans for Carrie, who died a day earlier.
Carrie's death certificate lists her cause of death as "cardiac arrest/deferred". The "deferred" designation indicates that more investigation is needed by the coroner, usually in the form of toxicology tests that can take several weeks to complete.
The certificate says the Star Wars actress had been in the entertainment business for 46 years.
Carrie became ill while on a flight from London to Los Angeles on December 23. She died aged 60 on December 27 at Ronald Reagan UCLA Medical Centre, the certificate adds.
The mother and daughter were remembered at a memorial at their neighbouring homes on Thursday and had a joint funeral at a Hollywood Hills cemetery the next day.
Relatives have said they are planning a public memorial.