Police were called to the supermarket on Esher High Street on Wednesday (August 20) shortly after 6pm to reports of a medical emergency.
Medics from the South East Coast Ambulance Service were treating a woman in her 40s.
She was pronounced dead at the scene.
There reportedly was a significant emergency services presence in the area.
Waitrose was also closed during the time.
A Surrey Police spokesperson said: “Officers were called to Waitrose on Esher High Street shortly after 6pm yesterday evening (Wednesday, 20 August) by the South East Coast Ambulance Service, who were responding to a medical emergency at the location.
“Despite the best efforts of paramedics, a woman in her 40s died at the scene. Her next of kin have been informed.
“There was a significant emergency services presence in the area, including police, South East Coast Ambulance Service, and the Air Ambulance Charity Kent, Surrey, Sussex. Waitrose was closed to allow emergency services to carry out their work, but has since reopened.”