ERC Chairman Jean-Pierre Lux said: "I am delighted to welcome Fiat as a partner to the Heineken Cup, European Challenge Cup and European Shield.
"Fiat is a major brand in all the countries where our tournaments are played and we look forward to working with them during what is a very important season for the Heineken Cup as it celebrates its tenth anniversary."
Mr Massimo Toso, Managing Director of Fiat Auto UK, said: "We are proud to be ERC tournament partners for the next year and be associated with the leading club rugby tournaments in Europe. We are confident this partnership will be of mutual benefit to Fiat and ERC and we look forward to an exciting season of top class European rugby."
Derek McGrath, ERC Chief Executive added: "Fiat are synonymous with elite sports sponsorship and I am delighted that ERC's tournaments are now also on that prestigious list. ERC have an excellent platform through the tournaments to deliver the right kind of exposure to the Fiat brand in the right places."