After months of negotiations with no agreement, more than 100 workers walked off the job at Univision-owned KMEX-TV Los Angeles.
The National Association of Broadcast Employees and Technicians says the workers are striking over job security and wages. Workers at the Spanish-language station have been without a contract since late March.
Patricia Ramos, spokeswoman for KMEX-TV, said: "It is disappointing that the union membership has decided to initiate a job action instead of seeking a resolution to the remaining key issues at the bargaining table, especially since there has been such dramatic and encouraging progress made during the last week."
The job action is the second one faced this year by the Spanish-language broadcaster. In the spring, NABET led a 43-day hunger strike at KFTV(TV) Fresno, before an agreement was reached.