[영문]This paper estimates net marginal Social Security tax rates, by age, for the cohorts of workers covered by Social Security in 2000, 2010, 2020 and 2030. The paper updates and extends Feldstein and Samwick's (1992) study. In contrast to their study, which found net tax rates much higher for young workers relative to older workers in 1990, this paper finds net tax rates to be relatively uniform across age groups. This paper's inclusion of the Disability Insurance program, the projected decline in future mortality rates, and the continued phase?in of higher retirement ages accounts for our sharply differing conclusions.