The agency picked up the account following a pitch involving PHD, OMD and incumbent agency Initiative. MediaCom will also look after the brand's online media account, which was formerly held by Zed Media.
The appointment comes a month after E.ON hired MVi, the digital division of MediaVest Manchester, to handle its search marketing account after a pitch against five undisclosed agencies.
In June E.ON appointed Jeremy Davies to its most senior marketing position. The former Abbey brand and communications director succeeded Gary Pepler.