Charles Gibson will step down as anchor of ABC's "World News" at the end of the year, the network announced Wednesday.
Gibson announced his resignation in an email to the "World News" staff.
"I have always been taught you should never bury the lead - so I write to tell you that I have told David Westin I want to step down as anchor of World News, and retire from full time employment at ABC News," he wrote.
"This has been my professional home for almost 35 years," he added. "And I love this news department, and all who work in it, to the depths of my soul."
ABC News President David Westin said he and Gibson have discussed the decision for weeks.
"I respect his decision, just as I respect the enormous contribution he has made to ABC News through the years," Westin wrote in an email to the ABC News staff.
Westin said he asked "Good Morning America" anchor Diane Sawyer to take Gibson's seat at the "World News" anchor desk in January 2010.
"Diane Sawyer is the right person to succeed Charlie and build on what he has accomplished," Westin wrote. "She has an outstanding and varied career in television journalism, beginning with her role as a State Department correspondent and continuing at 60 Minutes, Primetime Live, and Good Morning America."
Gibson has hosted the evening news broadcast since May of 2006. He said he plans to continue as a part-time contributor.
Beginning with Sawyer's new role in January, two of the three major network's evening news broadcasts will be anchored by females - a first in television history.