The pensioner, who has been named locally as Brigid McKeefry and is aged in her 70s, was rushed to the Causeway Hospital for treatment.
However she later died from her injuries and a post-mortem is taking place.
The tragic incident happened on the family farm off Carhill Road in Garvagh at about 2.30pm when the woman was attacked by cattle.
It is understood Mrs McKeefry had been working with livestock at the time.
DUP east Londonderry MLA Adrian McQuillan expressed his sympathies to the elderly woman's family.
Mr McQuillan said late last night: "This news is very shocking to the entire close-knit community of Garvagh and the surrounding areas.
"The family were well-known in the farming community and I understand the woman in her 70s was killed by cattle on the family farm, this evening.
"My thoughts and prayers are with the family during this deeply distressing time.
"The HSENI (Health and Safety Executive) will be carrying out investigations.
"Yesterday evening's incident serves as a reminder that there are many dangers that surround us on our farms.
"It is important that those working on farms take caution and follow all safety procedures."
A spokesman from the Health and Safety Executive (HSENI) said: "The HSENI can confirm it is currently investigating a serious incident on a farm in the Garvagh area, but is not in a position to make any further comment at this stage."
The Ambulance Service said that emergency services were called to the scene at around 2.30pm.
"A patient was taken from the scene to Causeway Hospital," a spokesman added.
It's the third farm tragedy to hit Northern Ireland in the last few weeks.
Yesterday's tragedy comes after the deaths of 30-year-old Co Tyrone farmer James Irwin -who was killed after becoming trapped in farm machinery - and Alastair Sloss, who died in a slurry accident last Friday.
And it comes just a month after another woman suffered horrific injuries after she was attacked by a cow in Co Fermanagh. Caroline Somerville from south Belfast had been visiting Devenish Island when she was attacked by the farm animal.
Her dog was also injured and later died.
sounds suspicious.... are those cows British by chance??? Inquiring minds need to know, as that would fit the pattern, and who knows but that one level reflects the one above it?