Refusing to back down from his blunt words about Roman Catholic bishops, Frank Keating, former governor of Oklahoma, resigned yesterday as chairman of the church-appointed panel that is seeking to resolve the sexual abuse scandal involving priests and minors.

''I make no apology,'' said Mr. Keating, who compared some bishops to ''La Cosa Nostra'' last week, suggesting that they were continuing to cover up the extent of molestation by members of the clergy.

His comments drew immediate condemnation from the archbishop of Los Angeles, Cardinal Roger M. Mahony, as well as from members of Mr. Keating's own panel, the National Review Board. The board was appointed by the United States Conference of Catholic Bishops to monitor compliance with anti-abuse policies established a year ago by the bishops.

In a letter to Bishop Wilton D. Gregory, president of the conference and the man who appointed him, Mr. Keating said he had intended to give up the job after his first year anyway; the position has no time limit. But he came under swift pressure to step down immediately because of the comments. Cardinal Mahony said he and other bishops would raise questions at the bishops' semiannual meeting this week in St. Louis about Mr. Keating's comments.