The 86-year-old man was walking in Waterside Street in Largs, North Ayrshire, when a lorry with no driver rolled down the street and struck a parked car.
The second vehicle then hit the man, trapping him underneath.
Firefighters and police rushed to the accident after being alerted at around 11.30am yesterday but the pensioner died at the scene.
Firefighters battled to free him from underneath a Peugeot 205, which also struck three other parked cars.
The parked cars were damaged in the collision, but no-one else was injured.
Eyewitnesses said a helicopter, believed to be an air ambulance, had landed nearby before leaving the scene.
Sergeant Mark McGowan called for public help with the investigation into what happened.
He said: "I would appeal to anyone who was in the area of Waterside Street, Largs, around 11.30am, and witnessed the crash to come forward."
Both New Street and Waterside Street were closed off following the tragedy.
The Health and Safety Executive has been informed of the incident and a report will be submitted to the procurator-fiscal.
One local said: "I have never seen so many police in Largs, it must be something big."
Another tweeted: "RIP to the man who just got ran over by a lorry in Largs, honestly terrible!"
In February, in the nearby village of Fairlie, Catherine Bonner, 55, died after being trapped under rubble when a runaway coal lorry smashed into her ground-floor flat.
Her husband, who was with her and their dog in the living room as the lorry came through the wall, suffered minor injuries.
The impact left the building standing - but only because the truck was left wedged into the corner of the block.
The 54-year-old truck driver was slightly injured and the only other person in the building at the time was rescued unhurt.