
However, during the negotiations, the parties could not agree on several key issues, including policies regarding health care, holidays, retirement benefits, and vacation time. On September 8 and 9, 2021, both sides submitted their proposals for a new contract and entered into discussions on them. While the contract between the union and company had expired in 2020, an extension renewed the existing contract until October 2021.

One worker, describing the situation at the Lancaster plant, compared it to a " death of a thousand cuts". The union and company had had a rough relationship over the past several years, with the company performing a lockout at their Memphis plant in 20, firing about 187 workers at their Battle Creek plant in 2018, and in September 2021, announcing that they would be firing about another 200 employees from that plant, a majority of whom would be union employees. Going into October 2021, the company had been negotiating for over a year with the Bakery, Confectionery, Tobacco Workers and Grain Millers' International Union (BCTGM), a labor union that represents about 1,400 workers at these plants. In the United States, the company operated four cereal-producing plants in Battle Creek, Michigan (also where the company is headquartered) Omaha, Nebraska Lancaster, Pennsylvania and Memphis, Tennessee. Kellogg's is an American food manufacturer that derives about a third of its profits from its line of breakfast cereals, which includes brands such as Froot Loops and Frosted Flakes. The strike ended after union workers voted to approve a new five-year labor contract. The strike is the first to affect Kellogg's Battle Creek plant since 1972, and the first at the Lancaster plant since 1985. It is one of several strikes conducted by the BCTGM in 2021, including strike action against Frito-Lay and Nabisco. The strike affected all of Kellogg's cereal-producing plants in the United States, consisting of plants in Battle Creek, Michigan Omaha, Nebraska Lancaster, Pennsylvania and Memphis, Tennessee.

The strike was caused due to disagreements between the union and company concerning the terms of a new labor contract, with particular points of contention concerning the current two-tier wage system (with legacy workers making $35/hr and new hires $22/hr), health care, holidays, retirement benefits, cost-of-living adjustments, and vacation time. The 2021 Kellogg's strike was a labor strike started on Octoand ended Deceminvolving about 1,400 workers for food manufacturer Kellogg's, unionized as members of the Bakery, Confectionery, Tobacco Workers and Grain Millers' International Union (BCTGM).
