Oxfam invited Publicis agency ZenithOptimedia, Feather Brooksbank, the7stars, Profero, Cheeze and incumbent All Response Media to pitch for the media and direct marketing accounts in July.
ZenithOptimedia will handle online and offline media planning and buying for the Oxford-based charity, worth an estimated £5.7m according to Nielsen Media Research.
The win excludes direct marketing, worth a further estimated £1m.
All Response Media and sister agency EHS Brann won the Oxfam media brief in June 2004, with ARM taking charge of media buying and EHS the direct mail activity.
The media review coincides with a creative review ahead of Oxfam's annual winter fundraising campaign and to promote its alternative gifts catalogue Oxfam Unwrapped.
In June, Oxfam appointed full-service agency Naked Communications and its design and creative agency Odd to handle youth marketing activity for its Oxfam Youth programme, using the new strapline: "Live your life, change the world".
Most recently, Oxfam and Xfm teamed up with youth volunteering organisation V to offer individual grants to participants in Oxjam, a month-long series of UK gigs featuring headline acts Kasabian, the Kooks and Fatboy Slim.
Oxfam and ZenithOptimedia declined to comment.