In 1998, Moonves became the president of CBS, and named Tellem his successor. That year Tellem ascended to the presidency of CBS Entertainment, where she oversaw programming, development, production, business affairs and network operations. She was responsible for deciding which shows appeared on CBS, supervised the prime-time, daytime, late-night and Saturday morning lineup on both CBS and The CW Television Network - the merged network of The WB and UPN - including shows like "CSI," "Survivor," "Everybody Loves Raymond" and "The King of Queens," and helped create the landmark shows "Friends" and "ER". In 2010, she stepped down as president, and took on a new role as a senior advisor to Moonves.