Diverse notions on the effectiveness of sport sponsorship have been discussed to some degree in literature on consumer psychology and shareholder wealth. However, there is little investigation on a micro-level that provides empirical evidence for financial returns resulting from sponsorship. In fact, few studies have explored issues related to the evaluation of sponsorship return on investment (ROI), particularly regarding the scope of measurement. This study investigates the effects of a major Olympic sponsorship on consumers’ actual soft drink choices. It analyzes Nielsen Homescan purchase data for over 10,000 American households for a 3-year period spanning Coca-Cola’s sponsorship of the 2006 Olympic Winter Games and the 2008 Summer Games. Our analysis indicates that Olympic sponsorship may have generated significantly greater consumer choices for Coke over Pepsi during the Games. The effectiveness of sponsorship is statistically supported, even after controlling for sales increases attributed to traditional media advertising. It demonstrates that evaluation of sponsorship ROI is empirically achievable.