Three dining halls at Harvard University are closing indefinitely as the staff strikes Wednesday morning.
The union says the workers have simple demands they say are not being met.
Workers went on strike at midnight and have been picketing before dawn.
Workers are asking for a $35,000-a-year income and guaranteed summer employment.
The school countered with an offer that included an increase in wages by 10-percent over five years and a summer stipend.
The university released a statement that read in part, "Over the past four months, Harvard has been committed to working with Local 26 in good faith to reach a new agreement that recognizes our colleagues' important contributions while supporting the University's core mission of research, teaching and learning."
It added, "We have proposed creative solutions to issues presented by the union, and hoped union representatives would contribute to finding creative, workable solutions at the negotiation table. They have been unwilling to do so. Harvard's negotiation team offered to stay though the night to continue to work on a deal, but Local 26 representatives left at 5:30 p.m. We are disappointed that they have been more interested in planning a strike than working on a solution that meets the needs of their members and the wider community."