Film and TV writers resolved to put down their pens and take up picket signs after last-ditch talks failed to avert a strike.
The first picket lines were set to appear Monday morning at Rockefeller Center in New York, where NBC is headquartered.
In Los Angeles, writers were planning to picket 14 studio locations in four-hour shifts from 9 a.m. to 5 p.m. each day until a new deal is reached.
The contract between the 12,000-member Writers Guild of America and the Alliance of Motion Picture and Television Producer expired Oct. 31. Talks that began this summer failed to produce much progress on the writers' key demands for a bigger slice of DVD profits and revenue from the distribution of films and TV shows over the Internet.
Writers and producers gathered for negotiations Sunday at the request of a federal mediator.
The two sides met for nearly 11 hours before East Coast members of the writers union announced on their Web site that the strike had begun for their 4,000 members.
Producers said writers refused a request to "stop the clock" on the planned strike while talks continued.
"It is unfortunate that they choose to take this irresponsible action," producers said in a statement.
Producers said writers were not willing to compromise on their major demands.
Writers said they withdrew a proposal to increase their share of revenue from the sale of DVDs that had been a stumbling block for producers. They also said the proposals by producers in the area of Internet reuse of TV episodes and films were unacceptable.
"The AMPTP made no response to any of the other proposals that the WGA has made since July," writers said in a statement.
The strike is the first walkout by writers since 1988. That work stoppage lasted 22 weeks and cost the industry more than $500 million.
The first casualty of the strike would be late-night talk shows, which are dependent on current events to fuel monologues and other entertainment.
Daytime TV, including live talk shows such as "The View" and soap operas, which typically tape about a week's worth of shows in advance, would be next to feel the impact.
The strike will not immediately impact production of movies or prime-time TV programs. Most studios have stockpiled dozens of movie scripts, and TV shows have enough scripts or completed shows in hand to last until early next year.
One key factor that could determine the damage caused by the strike is whether members of a powerful Hollywood Teamsters local honor the picket lines.
Local 399, which represents truck drivers, casting directors and location managers, had told its members that as a union, it has a legal obligation to honor its contracts with producers.
But the clause does not apply to individuals, who are protected by federal law from employer retribution if they decide to honor picket lines, the local said.
The battle has broad implications for the way Hollywood does business, since whatever deal is struck by writers will likely be used as a template for talks with actors and directors, whose contracts expire next June.
"We'll get what they get," Screen Actors Guild president Alan Rosenberg told The Associated Press.
The guilds have been preparing for these negotiations for years, hiring staff with extensive labor union experience, and developing joint strategies and a harder line than producers have seen in decades.
"We haven't shown particular resolve in past negotiations," said John Bowman, the WGA's chief negotiator.
From NPR reports and The Associated Press
Q&A: What's Behind the Hollywood Writers' Strike?
Film and television writers are going on strike, as talks have not produced a new contract between the Writers Guild of America and the Alliance of Motion Picture and Television Producers. The writers' demands include a percentage of DVD profits, plus a cut of money from new-media distribution. NPR.org offers this explainer.