Numerous U.S. cities have recently enacted taxes on sweetened beverages. To examine the effects of the beverage tax of 1.5 cents per ounce in Philadelphia, we surveyed adults and children in Philadelphia and nearby comparison communities both before the tax and nearly one year after implementation. We find that the tax reduced purchases in Philadelphia stores and that Philadelphia residents increased purchases of taxed beverages outside of the city. The tax reduced the frequency of adults’ soda consumption by 31 percent, but had no detectable impacts on adults’ consumption of other beverages. The tax had no detectable impact on children’s consumption of soda or all taxed beverages, although children who were frequent consumers prior to the tax reduced their consumption after the tax.