Conservative leaders told reporters Wednesday to urge lawmakers to reject any higher taxes.
The House of Representatives is expected to vote Thursday on a "Plan B" that would retain Bush-era tax cuts, but raise taxes on millionaires.
Don't do it, said the conservatives at a Capitol Hill news conference.
"As leaders of broad based American citizen groups we call upon Republican House Members to vote no on Speaker Boehner’s Tax Hike known as Plan B,"they said in a statement.
"Speaker Boehner, President Obama, Nancy Pelosi and too many Members of the Republican conference have forgotten that the problem in Washington is too much spending and not too little taxation.
"When the American people voted to return the Republican majority in the House last month we sent you to cut spending. Instead, you are now voting on the Pelosi plan to increase taxes next year. We urge Members of the House to vote no on the procedural rule to stop the Pelosi/Boehner tax plan from coming to the House floor for a vote."
Among those signing the statement: Edwin Meese III, former Reagan administration Attorney General; Brent Bozell, President, ForAmerica; Erick Erickson, Editor, RedState.com; Colin Hanna, President, Let Freedom Ring; J. Kenneth Blackwell, Ohio Faith & Freedom Coalition; Tony Perkins, President, Family Research Council; David N. Bossie, President, Citizens United; Alfred Regnery, President, The Paul Revere Project; William Wilson, President, Americans for Limited Government; Chris Chocola, President, Club for Growth; George Landrith, Frontiers of Freedom; Michael Needham, Chief Executive Officer, Heritage Action for America; Morton Blackwell, Chairman, The Weyrich Lunch; Peter Thomas, Chairman, The Conservative Caucus'; Amy Kremer, Chairman Tea Party Express; Richard Viguerie, Chairman, ConservativeHQ.com; David Y. Denholm, President, Public Service Research Council; Jim Backlin, Christian Coalition of America; Becky Norton Dunlop, former Reagan Administration official; Gary Bauer, President, American Values; David Williams, President, Taxpayers Protection Alliance; David McIntosh, former Member of Congress, Indiana; Robert (Bob) Reccord, Exec. Dir., Council for National Policy and T. Kenneth Cribb, former Domestic Advisor to President Reagan.