"It's been a wonderful 15 years," Phillips said in a statement. "I'm profoundly appreciative of the many friends and colleagues, past and present, who have been a part of the "Dateline" family. This is a great news division with a bright future. I wish the people of NBC News all the best."
Phillips previously had worked for ABC on news magazine "20/20." He had been with "Dateline" since its debut.
"He is a first-rate journalist and a dedicated professional whose legacy here will live on with the program he established and cares so much about," said Steve Capus, NBC News' president, in a statement.
"Dateline" is scheduled to air this fall on Saturdays at 8, and against "60 Minutes" Sundays starting next winter, after NBC's coverage of the NFL is complete. But the show, as it has many times before, could pop up in other spots as a utility player when scheduled shows are canceled.