The U.S.-based companies -- Google, Yahoo!, Microsoft and Cisco -- are reported to have altered online products for the Chinese market, such as search engines and blogging tools, to conform with the Chinese government's efforts to suppress dissent, The New York Times said.
The companies also reportedly sold Internet hardware to China to help that government spy on its own people online, and played a role in the imprisonment of Chinese online users for free speech that is protected in the West.
The criticism opened up long-awaited House hearings on the matter.
Rep. Christopher Shay, R-N.J., condemned the companies for what he called a "sickening collaboration" with China and for "decapitating the voice of the dissidents there."
Rep. Tom Lantos, D-Calif., said, "I do not understand how your corporate leadership sleeps at night."
Several company executives were expected to testify at the committee hearing.