It is well established that health, measured in various ways including chronic health conditions, is an important determinant of subjective age. This study investigates if new diagnoses of chronic health conditions are associated with subjective age and if the magnitude of such an association varies across chronological age. The study uses 2010 and 2014 waves of the Health and Retirement Study (HRS). Residualized change regression analysis was performed to examine the association between number of chronic health conditions newly diagnosed between 2010 - 2014 and change in subjective age in 2014 compared to 2010, using 2010 chronological age as a moderator. Results showed that every new diagnosis of chronic health condition was associated with a 0.68 year increase in subjective age in 2014, compared to their subjective age in 2010. However, this increase was attenuated by 0.06 for every 1-year increase in participants’ chronological age in 2010. These results can be understood with Social Comparison and Temporal Comparison theories, according to which individuals compare themselves to their peers and also to their earlier years of life. Compared to older adults, middle aged individuals are more likely to have healthier peers and also more likely to be healthy in their immediate prior years. Since multi morbidity is stereotypically associated with old age, chronic disease diagnoses may be seen as normative in older adults. However, new diagnosis of chronic health conditions may have a greater influence on subjective age in middle aged individuals.