CNN is canceling “Reliable Sources,” its long-running media affairs show, and the reporter who hosted it, Brian Stelter, is leaving the network, the company said on Thursday.

The show’s last edition would be on Aug. 21, according to a spokesman for CNN.

“We appreciate his contributions to the network and wish him well as he embarks on new endeavors,” the spokesman said.

Amy Entelis, CNN’s executive vice president for talent and content development, said in a statement that Mr. Stelter would depart CNN as “an impeccable broadcaster.”

“We are proud of what Brian and his team accomplished over the years, and we’re confident their impact and influence will long outlive the show,” Ms. Entelis said.

News of the show’s cancellation was earlier reported by NPR. Around the same time, Mr. Stelter joked on Twitter that his cellphone was nearly out of power, and that he’d picked a bad day to violate the “A.B.C. rule: always be charging.”

The cancellation of “Reliable Sources” puts Mr. Stelter, an inveterate media reporter with an unflagging presence on Twitter, in the unusual position of being at the center of a story in an industry he covers.

This is a developing story. Check back for updates.