Union leaders said they would delay the action if producers showed flexibility, especially on the issue of paying writers when television episodes are sold or streamed over the internet.
"We have 48 hours, and what we really want to do is negotiate," said John Bowman, chairman of the union's negotiating committee.
He said that while reluctant to go on strike, the Writers Guild felt it had to act decisively.
"We have to inflict as much damage as quickly as possible in order to get this thing over," Bowman said.
While the revenue generated by internet sales and rentals is tiny compared to DVDs, the union said internet revenue will eventually become dominant.
Nick Counter, president of the Alliance of Motion Picture and Television Producers, said his group was ready to meet and finish negotiations over the weekend.
The strike is likely to first affect late-night talk shows, which are dependent on scripts written around current events.
On his show on Thursday, David Letterman described the producers as "cowards, cutthroats and weasels."
Film and prime-time television productions are not expected to immediately be impacted by the strike.
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.
Consumers are expected to spend $16.4bn on DVDs this year, according to Adams Media Research.
By contrast, studios are likely to only generate about $158m from selling movies online and about $194m from selling TV shows over the web.
The studios argue that it is too early to know how much money they can make from offering entertainment on the internet, cell phones, iPods and other devices.
The guild's last strike, in 1988, lasted 22 weeks and cost the industry about $500m.
Jack Kyser, a Los Angelese economist, said a strike of the same duration today could result in at least $1 billion in economic losses.