“When you cannot measure, your knowledge is meager and unsatisfactory”—Lord Kelvin. (Chiseled on the archway of the University of Chicago Social Sciences Building). The United States Bureau of the Census provides official poverty rates for most vulnerable populations in the United States, but does not do so for working-age people with disabilities. This paper creates a comparable poverty measure for those with and without disabilities using March Current Population Surveys (CPS) for the years 1981-2004. In contrast to other vulnerable populations whose economic well-being improved substantially over the 1990s, the poverty rate of working-age people with disabilities increased both absolutely and relative to working-age people without disabilities over both the 1980s and 1990s business cycles. The first step in reversing this socially unacceptable trend is for the United States government to provide an official poverty rate measure of the working-age population with disabilities both to better tract the progress of this economically vulnerable and little understood population and to determine the causes for the absolute and relative increase in their risk of poverty.