Up to 70 jobs are being lost at Elanco vaccine manufacturing facility in Co Sligo.
The animal health company says it is due to restructuring at the firm.
The company says Sligo will continue to be the commercialisation, label and packaging hub for Europe, and there will be no impact on products made there.
"These changes, while very difficult, are necessary to position the facility to continue to provide high quality, cost-effective products for Elanco customers and meet long-term business needs", it says in a statement.
Details of the job losses were given to staff at a meeting yesterday.
A 30-day statutory consultation phase will get underway to help employees examine any options that may be available to them.