Abstract: Despite significant efforts to further reduce HIV incidence, including the introduction and scaling of pre-exposure prophylaxis (PrEP) in 2012, the repeal of the "Don't Ask, Don't Tell" (DADT) policy in 2011, and test-and-treat initiatives aligned with the 2019 "Ending the HIV Epidemic" initiative, annual rates of HIV incidence in the U.S. Armed Forces have continued to show little to no annual declines. To better understand the nature of new infections in the U.S. military, this retrospective analysis examined cases and trends in greater depth to 1) identify and describe total HIV antibody seropositivity rates from 1990 to 2024, with stratification by demographic characteristics, and 2) identify and characterize potential shifts in the epidemiological profile of HIV cases during the course of the evolving HIV epidemic. From January 1990 through December 2024, over 46 million U.S. service members in the active component, Guard, and reserve were tested for HIV antibodies, and 11,280 (24.3 per 100,000 persons tested) were diagnosed with HIV. Male service members comprised 96.3% of all HIV infections. The total rate of new HIV diagnoses declined over the period of surveillance, with the steepest decline in the first decade. Overall rates stabilized in 1997, but differences persist between different age and population groups. New HIV diagnoses have risen among male service members under age 30 years, with non-Hispanic Black service members bearing the highest burden and Hispanic service members experiencing the largest relative increases. Since 1997, rates in all racial and ethnic groups have more than doubled for those under age 25 years; for Hispanic service members, the increase was nearly 10-fold.