The appointment, which was made without a pitch, comes as a result of Bauer's acquisition of Emap Radio in January. Starcom has handled media for Emap's Magic, Kerrang! and Kiss FM stations since 2001.
Starcom gains the media account for the Big City network of stations in England, Scotland and Northern Ireland, including Key 103 in Manchester and City Talk in Liverpool. In addition, the agency will handle media for Bauer's digital stations Heat and Closer.
Steve Parkinson, the marketing director for Bauer Radio, said: "We are delighted to extend our relationship with Starcom as we enter an exciting new period as Bauer Radio. This year will see a multimillion-pound investment across the portfolio. We will drive growth across our heritage stations around the UK and invest further in launches such as City Talk in Liverpool and digital stations."
Chris Locke, the Starcom MediaVest group trading director, said: "As the UK's number-one radio spender, we have a passion for the medium. Not only how our other clients can engage with it on its various platforms, but how media owners like Bauer need to engage with consumers."