His announcement came four days after former Federal Reserve chairman Paul Volcker urged top management to step aside so he can install and head an independent board in a last-ditch plan to save the company.
The key element of Volcker's plan is the dismissal of a federal indictment against Andersen alleging obstruction of justice in destroying Enron-related documents. The Justice Department has not said whether it would consider such an action.
Berardino disclosed his decision late Tuesday as Andersen partners, in internal company e-mails, were stepping up pressure on him to quit. He said he would remain in charge temporarily until a successor is chosen.
"I felt I had to take this step today to put an exclamation point behind the voices of our people ... to say that we are serious and we're a serious firm that deserves to continue here in the United States," Berardino told CNN.
"We're in deep stress," he said of the 89-year-old Chicago firm.
Andersen has lost more than 70 clients this year in the wake of the scandal involving its auditing client Enron, and its overseas affiliates have been bolting to rival firms. Industry experts are doubtful whether Volcker's plan or any other can prevent the firm from folding.
Volcker, who heads an oversight committee charged with making sweeping reforms at the company, has also said a cap must be placed on Andersen's financial liability from the Enron scandal if it is to survive.
Andersen's 1,700 partners have been urging Berardino to resign, according to several partners interviewed Tuesday. Retired partners also have been pushing for his ouster in hopes it can help keep Andersen afloat.
Since the indictment, he hasn't communicated well with the partners.
His resignation, said Chicago-based partner Kathy Scherer, may be "the only way that the Justice Department might ease up" on Andersen.
"I'm not sure they would consider pulling the indictment," she said. "But to indict and try Paul Volcker would be difficult, given the man's standing."
Berardino, the head of Andersen since January 2001, also is managing partner-chief executive of Andersen Worldwide, the legal parent of Arthur Andersen.
A person familiar with the situation said Andersen's board is flying to London this week to talk about a succession plan, even as discussions continue about combining its non-U.S. operations with those of rival KPMG.
Before becoming CEO, Berardino was managing partner for the company's assurance and business advisory practice in North America. He has been with the firm since 1972.