Workers at Amazon's main distribution hub in Italy are planning their first ever strike for Friday, trade unions said.
Amazon staff are also striking at six warehouses in Germany, threatening to disrupt one of the year's busiest shopping days.
Like the rest of Europe, Italians in recent years have embraced the US tradition of Black Friday, a day of heavy discounting by retailers on the day after Thanksgiving.
Unions said in a statement more than 500 Amazon workers at the Piacenza site in northern Italy had agreed to strike following a failure to negotiate bonuses with the company.
Workers have also decided not to do any overtime until December 31, covering the peak season for the online retailer which hires temporary workers during this period.
Amazon employs around 1,600 people on a permanent basis at the Piacenza site, the first it built in the country after launching its Italian website in 2010.
The Verdi trade union in Germany said Amazon employees would also strike on Friday at six distribution centres in the country as part of a long-running dispute over pay and conditions.
"The world's biggest online retailer wants to achieve record sales on this day, but employees have to produce record performance not only on this day so that everything runs how Amazon wants it," said Verdi board member Stefanie Nutzenberger.
Amazon in Italy said in a statement it remained focused ontrying to guarantee scheduled deliveries for its customers on Black Friday and in the following days.
The company said salaries paid to its workers were among the highest in the logistic sector and that it also provided some benefits such as private medical insurance or money to pay for training programmes.