Technology group Microsemi is closing its Ennis plant with the loss of 131 jobs.
The US company, which manufactures semiconductors, said it had decided to consolidate operations at two factories in the United States. One of the company's US plants is also closing.
Altogether, the company is shedding 1,211 jobs in a restructuring it hopes will generate annual savings of between $6 million (€4.7 million) and $10 million.
Microsemi said it would incur costs of between $9 million and $12 million over the next 12-18 months as the jobs are phased out.
A statement from Microsemi said the closure "follows a corporate decision to consolidate production in the company's US facilities in Scottsdale, Arizona and Lawrence, Massachusetts".
The jobs lost include 44 permanent and 87 temporary posts. A 15-strong European sales and marketing team is not affected by the decision. The company said it would be "providing a generous redundancy package and outplacement services for the individuals involved".
Microsemi Ireland general manager Richard Finn said: "The closure of the Irish manufacturing operation is necessary, in order to maximise economy of manufacturing scale for the overall Microsemi group.
He said the company regretted having to close the plant but described the move as "necessary for the ongoing competitiveness of our business".
Microsemi, which has been based in Ennis since 1992 was recruiting staff as recently as last month.
It designs and manufactures analog, mixed signal and discreet semiconductors. The company employs just over 1,400 staff worldwide with an annual turnover of €300 million.
Ennis Chamber of Commerce president John Galvin said the plant's closure "is very sad and unexpected".
Chamber chief executive Rita McInerney said the decision brought to 580 the number of manufacturing jobs lost in the town in the past five years.
Fine Gael TD Pat Breen said yesterday's announcement "left 131 people without a job and without much hope of finding one in the Ennis area".
He said there had been no major investment in Ennis in 14 years and the area was now an "under-invested ghost town"
