Shelf nutrition labels provide summary information on the overall nutritional quality of a food product. They provide cues to shoppers and may be effective in promoting healthy food choices at the point of purchase. The objective of this study was to explore the impact of NuVal Labels, a shelf nutrition label that rates the nutritional quality of foods, on food-purchasing patterns after NuVal underwent a change in algorithm. The study collected retail scanner data on weekly yogurt sales provided by a regional grocery chain, as well as survey data from an adult population that shops at 1 of 2 supermarket chains in the United States that uses NuVal. The study found that a 1-point increase in the NuVal score is estimated to increase sales of the corresponding yogurt product by 0.49%. However, only 8% of individuals surveyed reported using NuVal to influence their purchases.