The 43-year-old worker suffocated after 5 tonnes of grapes fell from a loading hopper at a vineyard in Tomelloso in central Spain.
Emergency service workers were called in after the incident, which took place at around 9pm on Thursday.
They were, however, unable to resuscitate the man.
He was pronounced dead at the scene at 10.30pm.
Tomelloso is considered the capital of wine growing in Spain's Castile–La Mancha region.