Former White House chief of staff Donald T. Regan has exaggerated the role of astrology in White House decision-making and unfairly pilloried President Reagan as an unassertive leader, Reagan's chief of staff said Wednesday.

Howard H. Baker Jr., speaking to reporters at the White House, was asked whether he believed Regan's book, "For the Record," unfairly portrayed first lady Nancy Reagan and her husband.

I really do think that. As I say, I am with the president every day, most of the day-- and I can tell you first-hand, I've never seen any decision, certainly no policy decision, that has ever been affected either by the first lady's input or by astrology," Baker said.

Regan's book, which revealed Mrs. Reagan's interest in astrology, painted a picture of an incurious, passive chief executive manipulated by a strong-willed wife and media-conscious staff.

Baker said the president does have "a great respect for the first lady's judgment -- she has good judgment, she has good instincts and intuition."