Life expectancy has risen markedly over the past century, but the gap between higher-income individuals and those lower on the socioeconomic distribution has been expanding. The health economics literature often focuses on health developments ex-post (e.g., working with mortality) or using measures such as self-assessment health questions. In this context, recent medical developments provided the possibility to assess in a prompt and objective way individuals’ health status. Via easily accessible measures (e.g., standard blood analyses) it is possible to estimate individuals’ Biological Age (BA), i.e., the “true” age level that individuals’ body present. People actually age at different rates and BA provides a potentially more accurate and useful variable to take into account. In this context, with my thesis, I plan to introduce BA into the analysis of inequality. Using the data of the US Health and Retirement Study (HRS), I examine the extent to which income affects the “age acceleration”, i.e., the difference between individuals’ Biological and Chronological Age.