The present study examined the demographic correlates of gene expression in a sample of adults (n = 543) from the Study of Midlife in the United States (MIDUS). Inflammatory and antiviral gene sets were operationalized using a priori composite scores and empirically derived co-regulatory gene sets. For both composite scores and co-regulatory gene sets, White/European Americans showed lower while Black/African Americans showed higher expression of genes involved in interferon responses and antibody synthesis. The effects of chronological age on gene expression varied by sex, such that pro-inflammatory gene expression increased with age more rapidly for females than males. The difference between the average expression of inflammatory and antiviral genes also increased with age for females but not males. Results shed light on differential gene expression as a potential physiological correlate for race/ethnicity, age, and sex-related health disparities in adulthood.