Justice Department internal investagitors have cleared Associate Attorney General Rudolph W. Giuliani of any wrongdoing in meeting with an attorney from McDonnell Douglas Corp. to discuss settlement of a pending criminal case.

The meeting caused a small furor last month when two department attorneys handling the overseas bribery case against the St. Louis firm told Giuliani in a letter that they hadn't known about the meeting and questioned its "wisdom and propriety." Fred Wertheimer, president of Common Cause, then asked for a review of Giuliani's conduct.

In a letter to Wertheimer Monday, Richard M. Rogers, acting head of the office of professional responsibility of Justice, said Giuliani's actions violated no department rule or regulation, did not constitute abuse of authority and were "a permissible exercise of his discretion."

Wertheimer said yesterday that he hadn't received the letter yet. "His conduct may have been permissible, but it would be disastrous for the system if it became a regular activity."

Justice spokesman Tom DeCair said yesterday that Giuliani still was reviewing the fraud charges against McDonnell Douglas and four of its executives to determine whether the case should be settled before trial.

The U.S. Court of Appeals here ruled last week that the defendants could not appeal a claim of vindictive prosecution before the trial. The trial judge also directed the Justice Department to report by the end of this week who would be its new attorneys on the case.

Michael a. Lubin and George J. Mendeslson, the case prosecutors who complained to Giuliani, have announced they are leaving the department for reasons unrelated to the internal dispute.