Consumer demands for labeling of genetically modified (GM) food products have the potential to dramatically impact the way food crops are produced and distributed in the U.S. In May 2014 Vermont became the first U.S. state to legally require the labeling of GM foods. This study uses several waves of data from an annual survey of Vermont households to explore consumer preference heterogeneity surrounding GM foods as well as changes in demographic and attitudinal determinants of demand for GM food labels since the year 2000. Findings suggest women, some high-income respondents, and relatively educated respondents have consistently been more opposed to GM foods over time, but that opposition to GM foods has decreased over time in other demographic groups, especially women. But at the same time, since 2000 the demand for GM labels has steadily increased among all demographic groups in Vermont, including both pro-GM and anti-GM respondents, reaching 96% support for labeling in 2013.