NEW YORK — ABC News said Charles Gibson is retiring and Diane Sawyer will replace him as the anchor of "World News."

Sawyer's elevation means that, with Katie Couric, two of the three leading anchors for the broadcast networks will be women.

Gibson said he had been planning to retire at the end of 2007 but events compelled him to stay. He was named anchor following the death of Peter Jennings and the wartime injury of Bob Woodruff.

He has been at ABC News for 35 years and said he plans to continue as an occasional contributor.

Gibson took over the ratings lead shortly after he took over at "World News." But he was eventually passed by NBC's Brian Williams, who has led in the ratings for nearly a year.