<p><b>BACKGROUND AND OBJECTIVES: </b>Sleep disordered breathing (SDB) is a risk factor of stroke and Alzheimer disease and related dementias (ADRDs). Hispanic/Latino adults have higher risk of SDB and ADRDs, which emphasizes the need to better understand the association between SDB and brain health. Furthermore, results on SDB and brain aging are mixed, and there are limited data for Hispanic/Latino adults. The main goal of this study is to assess the association between SDB and brain MRI measures in a diverse Hispanic/Latino population.</p><p><b>METHODS: </b>The Hispanic Community Health Study/Study of Latinos (HCHS/SOL) is a community-based prospective cohort multisite (Bronx, Chicago, Miami, San Diego) study of diverse Hispanic/Latino adults in the United States. Participants underwent 1 night of unsupervised home testing with a sleep apnea test device at baseline. The SOL-Investigation of Neurocognitive Aging MRI, an ancillary study, recruited 2,667 HCHS/SOL participants (35-85 years) who underwent neuroimaging approximately 10 years after baseline sleep assessment. The main exposure was the respiratory event index (REI, 3% desaturation). Secondary exposures encompassed measures of oxygen saturation. Main outcomes included total brain, gray matter, white matter hyperintensity (WMH), and hippocampal volumes. Survey linear regression models were used to determine associations between SDB and brain MRI measures.</p><p><b>RESULTS: </b>The mean age was 67.6 years, with a body mass index of 29.7, and 58.3% were female. We found that increased REI was associated with larger hippocampal volumes ( = 0.006 [0.001-0.012]). These results were consistent with oxygen levels (minimum SpO%) during sleep ( = -0.013 [-0.021 to -0.004]). Lower oxygen levels (mean SpO) during sleep were associated with enlarged WMH volumes ( = -0.095 [-0.164 to -0.025]).</p><p><b>DISCUSSION: </b>We found that SDB and worse oxygenation during sleep were linked to larger hippocampal volumes. These results underscore the complex relationships between sleep health and brain aging and warrant longitudinal follow-up, starting in middle age or earlier.</p>