I examine the differential responsiveness of U.S. senators to the preferences of rich and poor constituents. My analysis includes broad summary measures of senators’ roll call voting behavior as well as specific votes on the minimum wage, civil rights, government spending, and abortion. In every instance, senators appear to be much more responsive to the opinions of affluent constituents than to the opinions of constituents with modest incomes. On average, my estimates suggest that constituents at the 75th percentile of the income distribution have almost three times as much influence on senators’ general voting patterns as those at the 25th percentile, and several times as much influence on specific salient roll call votes. The preferences of constituents near the top of the income distribution are even more influential, while those in the bottom fifth receive little or no weight, especially from Republican senators. In the domain of ideology the disproportional influence of affluent constituents seems partly attributable to their greater propensity to vote and to contact senators and their staffs; in the domain of abortion the impact of income does not seem to be mediated by turnout, contacting, or political knowledge, and may reflect the dependence of elected officials on campaign contributions from pro-choice and pro-life activists.