Workers at Motorola in Cork city were called to meetings with managers today to be told that their jobs would be gone within the next six weeks.
330 of the 350 staff there are to lose their jobs.
Most of the workers will be gone by the end of the month; others will go at the end of April and the plant will be shut down by the end of May.
Motorola has been in Cork for the past 26 years. The company once employed around 500 people in the city. But when the plant closes, just 20 employees will be left in Cork.
In a statement to RTE News last night, Motorola confirmed that a month of consultations with staff had failed to provide a basis for continuing its operations in Cork.
Motorola is is desperately trying to cut costs after profits were halved in the final quarter of last year. The plant in Cork - a key production centre - is paying heavily for the cutbacks.
Having decided to cease all engineering functions in Cork, Motorola says the plant has became unavailable. The company has praised the professionalism and talent of the staff and has promised to help in the search for new jobs.