The relationship between nutrition knowledge and consumers’ food behavior has been debated for years. This may be partially attributed to the difficulty introduce by endogeneity of nutrition knowledge in econometric modeling. Using grass-fed beef as a vehicle, this paper investigates the impacts of consumers’ nutrition knowledge on their willingness to pay by accommodating the endogeneity problem using instrumental variable approach. Our results suggest that consumers’ nutrition knowledge significantly influences their willingness to pay for grass-fed beef. Gender and education are influential factors of consumers’ nutrition knowledge level.