Employees being trained in New Mexico and Arizona will come back to Ireland in December -- months earlier than expected.
Intel bosses are understood to have made the decision after a slowdown in demand for a new product.
The Leixlip facility was given a major boost earlier this year when it was announced that it was one of three campuses that would be chosen to produce a new nanometer microchip -- known as the "1272 process".
It prompted bosses there to order the refitting of the plants in Kildare in order to ensure that they are ready for the new technology.
But the news has now sparked fears among the 4,500 workers based in Leixlip, who have begun to worry about the long-term future of their jobs.
The company, which is one the largest private employers in Ireland, stated that it still intends to launch the new product at the Kildare factory.
A spokesperson reassured staff, and said that the company's "overall plans" had not changed.
"We regularly make adjustments to our factory workforce to optimise the talent we have available, wherever the need arises and dependent on economic condition," the spokesperson added.