The Dutch-owned finance company is a major investor in Formula One - currently investing £40m per year - and is title sponsor of the ING Renault F1 Team. The brand is also the title sponsor for both the Australian and Belgian Grand Prix.
The agency was awarded the multimillion-pound account following a final pitch against VCCP. It was overseen directly by Gabor Dani, marketing manager for ING's Formula One programme.
Iris will now create a range of campaigns spanning TV, direct, press advertising, online and experiential marketing. It is understood that the first work is due to break ahead of the ING Australian Grand Prix in March.
Having won the World Championships in 2005 and 2006, Renault has endured a difficult 2007. The team finished the season in third place in the Constructors World Championships behind Ferrari and BMW Sauber in Brazil last weekend. The team's Finnish driver, Heikki Kovalainen, and Italian Giancarlo Fisichella finished the season in seventh and eighth places respectively.
Last Sunday, ITV1 pulled in an estimated 7m viewers for the conclusion of an epic Formula One season, which saw Ferrari star Kimi Raikkonen pip McLaren drivers Lewis Hamilton and Fernando Alonso to the World Championship.
According to ITV, the audience peaked at 10.6m for the closing stages of the race, the highest figure for Formula One coverage since 2000.
The pitch also involved RGA, Glue London, Inferno and Exposure.
Media planning and buying will continue to be managed by ING's local agencies around the world.