Abstract Maintaining a healthy weight and cardiovascular health (CVH) after a breast cancer (BC) diagnosis is gaining clinical attention because they are essential for reducing the burden of cardiovascular disease, achieving optimal cancer survivorship, and possibly reducing mortality after a BC diagnosis. Individual behaviors and choices are largely influenced by the surrounding social and built environment; however, the neighborhood risk factors influencing post-diagnosis weight change and CVH are unclear among Black women, who have higher rates of obesity, unfavorable CVH and mortality than any other racial/ethnic group. To address this knowledge gap, we conducted analyses based on the Women's Circle of Health Follow-Up Study (WCHFS), a population-based prospective cohort of Black BC survivors in New Jersey. In the first analysis, adiposity changes during the period ~10 months to 2 years after diagnosis were evaluated among 785 women enrolled in the WCHFS. We found that despite a high baseline prevalence of overweight or obesity, weight gain was common. Greater density of fast-food restaurants and lower walkability were identified as neighborhood-level risk factors for weight gain. We also showed that intentional weight loss was much less common than weight gain, and its neighborhood risk factors were considerably different from unintentional weight loss. In a subsequent analysis, we aimed to capture the complex interplay between neighborhood features through neighborhood archetype analysis based on 16 social and built environment features, and to estimate their associations with CVH around 2 years after diagnosis among Black women. The CVH index used American Heart Association definition and scoring criteria for BMI, diet, smoking, physical activity, blood pressure, cholesterol, glucose, and sleep. We found that Black BC survivors, on average, reached only half of the recommended optimal CVH score, and no participant met all ideal CVH metrics. Among the four neighborhood archetypes identified, we found that the archetype associated with the most favorable post-diagnostic CVH was characterized by diverse racial and ethnic populations, a higher neighborhood socioeconomic status, greater densities of restaurants, food stores, physical activity facilities, walkable destinations, and ambulatory care. However, only 16% of our participants lived in this type of neighborhood. In summary, our work revealed that residential environments may considerably impact adiposity change and CVH among Black BC survivors. Through these studies, we provided insights into the distinct neighborhood characteristics and archetypes that may influence BC survivorship for Black women. Recognizing that social determinants of health act at multiple levels, domains, and factors, it is crucial that future research comprehensively investigates neighborhood and other multilevel determinants to identify the specific social barriers that must be addressed to achieve the most measurable improvements in BC survivorship for Black women. Citation Format: Bo Qin, Carola T. Sánchez-Díaz, Hari S. Iyer, Noreen Goldman, Nur Zeinomar, Andrew G. Rundle, Christine B. Ambrosone, Kitaw Demissie, Chi-Chen Hong, Gina S. Lovasi, Elisa V. Bandera. Neighborhood factors for adiposity change and cardiovascular health among Black breast cancer survivors [abstract]. In: Proceedings of the 16th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2023 Sep 29-Oct 2;Orlando, FL. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2023;32(12 Suppl):Abstract nr IA038.