Almost 2,000 Wilko workers are set to walk out at two major distribution centres in a war over seven-day working hours.
Union GMB, which represents staff members, said employees will take action over forced weekend shifts.
Around 1,800 GMB members at two Wilko warehouses – in Magor, Wales and Worksop, Nottinghamshire – will strike as a result of the changes.
This will take place from 6am on Friday 11 October 2019 until 05.59 on Saturday 12 October and then again on 14 October.
Gary Carter, GMB National Officer, said: “It is sad that it has come to this. We have done everything we can to try to negotiate a reduction in the amount of weekend working, but the offer from management is not acceptable.
“Wilko has always considered itself a family company - yet they’re forcing contracts on staff that will seriously impose on family time and workers’ wellbeing.

“GMB members will stand together and show Wilko management how strongly we feel about these harsh new contracts.”
In a statement to Mirror Money, Wilko previously denied any changes, stating the seven-day working arrangements are already written in all employee contracts.
However, staff told us .
"We share our team members frustrations and we remain committed to working with them and their representatives to further reduce the number of weekends they need to work, so that they can spend as much time as possible with their families," a spokesman said.
“We hear the feedback from the ballot and are keen to resolve any differences as quickly as possible as we don’t believe strike action is in anyone’s best interest at this challenging time for both retail in general and the High Street.
“The reality is that our customers expect to shop with us seven days a week and we must respond to meet our customers’ needs. The requirement for more regular weekend working in logistics continues and we are only asking team members to work within their existing contracts.
“There are robust plans in place to ensure customers can continue to shop with us if any action occurs.”