Abstract Disclosure: A. Atri: None. C. Anastasopoulou: None. Introduction: Vitamin D (Vit D) plays a critical role in maintaining bone mineralization and its deficiency adversely impacts bone health. Contemporary trends of Vit D deficiency (VDD) and racial-ethnic differences in these trends among US women with low bone mineral density (BMD) are not well elucidated. Methods: We used data from the National Health and Nutrition Examination Survey (NHANES) for the years 2009-10, 2013–14 and 2017–18 to include U.S. women ≥ 50 years with femoral neck T score ≤ -1. Osteoporosis was defined by a T-score ≤ -2.5. BMD assessment in NHANES was not completed in 2011–12 and 2015–16, and therefore not included in the analysis. Femoral neck BMD was measured by dual energy x-ray absorptiometry (DEXA) on Hologic Discovery Model A Densitometers (Hologic, Inc., Bedford, Massachusetts). VDD was defined as serum 25(OH)D <30 nmol/L. Participants with missing data on race-ethnicity, BMD and Vit D data were excluded. Independent samples median test was used for comparing medians. The Cochran-Armitage test was utilized for trend analysis. Results: Overall, in women with low BMD, from 2009-10 to 2017-18, prevalence of osteoporosis increased from 13.7% to 16.9% while VDD decreased significantly from 5.6% to 2.3% (p trend = 0.001). When stratified by race-ethnicity, the prevalence of osteoporosis increased in Whites (14.1% to 17.6%, p trend = 0.001), Hispanics (12.6% to 13.7%, p trend = 0.001) and Other race-ethnicity (Asian/Mixed) (14.1% to 21.4%, p trend = 0.001), but a modest decrease was noted among the Black population (7.3% to 6.8%, p trend = 0.001). VDD was disproportionately high among Blacks (In 2009-10: 28.1% vs 4.2% in Whites, 5.4% in Hispanics and 10.7% among Others). However, significantly improving trends in VDD were observed among all the groups, regardless of race/ethnicity, to 12.5% prevalence among Blacks, 1.3% in Whites, 4.9% in Hispanics and 1.1% in the Other race ethnicity group (p trend = 0.001). Discussion In this contemporary analysis, rates of VDD have decreased from nearly 1 in 20 to 1 in 50 women with low BMD in the US. Highest prevalence of VDD was noted among Blacks, seen in nearly 1 in 3 Black women in 2009-10, with improvement to 1 in 8, in 2017-18. Similar favorable trends of decline in VDD were observed across all other racial-ethnic groups as well. Despite the overall improvement in VDD, prevalence of osteoporosis declined only among Black women, suggesting the potential role of other protective factors against osteoporosis among them. Nevertheless, VDD continues to remain prevalent in this high-risk group, emphasizing the need for public health interventions to bridge this gap. Presentation: 6/2/2024