Geographic Information Systems (GIS) was a theme for one of the four workgroups convened for the Measures of the Food and Built Environment meeting held in Bethesda, Maryland in November 2007. This summary of group discussions frames several critical conceptual, methodologic, and data challenges regarding the use of GIS to enhance research relevant to policy on diet, physical activity, and weight. Broad recommendations are offered in five areas: (1) theoretical and conceptual development in framing place effects on health; (2) contextualizing people and spatial behavior in built environments and improving empirical representations of place; (3) geospatial data availability, quality, and standards; (4) privacy and confidentiality; and, (5) building capacity in GIS personnel and infrastructure. These topics are inter-related. Although our discussion focuses on issues relevant to the role of the built environment in diet and physical activity outcomes, our recommendations also are salient to health and environment research generally.