Their contract with the Alliance of Motion Picture and Television Producers is set to expire at midnight on the West Coast, so Writers Guild members took to the streets with other protesting laborers to demand better pay and health care.
Before marching, WGA members and AFM Local 47, the Musicians Union of Hollywood, joined together for a group photo.
Around 30 WGA members joined the tens of thousands from other unions and organizations.
Laura Blum-Smith, a WGA staff member, joined in chants for justice and immigrants' rights.
Some members expressed a general uncertainty about the outcome of today's negotiations but said they were prepared to strike if necessary.
Writer Maria Elena explained how she took part in the last WGA strike in 2007-2008.
WGA and Musicians Union of Hollywood members marched side by side.
