Objective: Black populations show increased incidences of diagnosis, worse disease severity, and earlier likelihood of mortality due to MS. Clinical outcomes are also linked to biological sex and as with Black individuals, MS characteristics between sexes have also shifted overtime. This study examined whether clinical disease progression differed by race and sex for patients with MS., Design: "Black" (N = 47) and "White" (N = 58) participants with MS (82 % female) were recruited from a longitudinal examination of the impact of race and sex on the cognition and disease duration of patients in the gulf south region of the United States., Results: Black participants had shorter disease durations [F (1,103) = 4.70, p = .03], (MDiff = [-3.96]) and were younger [F (1, 103) = 14.25, p < .001], (MDiff = [-9.04]). Despite this, Black individuals had worse SDMT t-scores [F (1, 103) = 5.22, p = .024], (MDiff = [-4.62])]. Women exhibited higher MSSS scores [F (1, 96) = 5.59, p = .02], (MDiff = [-2.15]). Specifically, Black women were younger than White women [F (1, 84) = 14.47, p < .001], (MDiff = [-9.15])] and had shorter disease durations [F (1, 84) = 6.04, p = .016], (MDiff = [-4.57])] yet scored lower on the SDMT T-scores [F (1, 84) = 6.11, p = .015], (MDiff = [-5.51])]., Conclusion: Findings suggest an interaction between race and sex may influence clinical progression in MS. Despite being younger and having shorter disease durations Black participants with MS, specifically Black women exhibited worse clinical outcomes., Summary: For women and men, MS incidence among Black Americans has become similar to White Americans. However, Black individuals experience greater disease severity and earlier mortality. Clinical impairment often accompanies MS. We examined the influence of race and sex on clinical status using the Symbol Digit Modalities Test t-scores (SDMT T-scores) and Multiple Sclerosis Severity Scores (MSSS) in Black (N = 47) and White (N = 58) patients with MS. Women exhibited higher MSSS scores than men [F (1, 96) = 5.59, p = .02], (MDiff = [-2.15]). Black participants had shorter disease durations [F (1, 103) = 4.70, p = .03], (MDiff = [-3.96]) and were younger [F (1, 103) = 14.25, p < .001], (MDiff = [-9.04]). Despite this, Black individuals had worse SDMT T-scores [F (1, 103) = 5.22, p = .024], (MDiff = [-4.62])]. Specifically, Black women were younger than White women [F (1, 84) = 14.47, p < .001], (MDiff = [-9.15])] and had shorter disease durations [F (1, 84) = 6.04, p = .016], (MDiff = [-4.57])] yet scored lower on the SDMT T-scores [F (1, 84) = 6.11, p = .015], (MDiff = [-5.51])]. These findings suggest that an interaction between race and sex may influence clinical progression in MS., Competing Interests: Declaration of competing interest The authors have no competing interest nor relevant financial or non-financial interests to disclose., (Copyright © 2024 Elsevier B.V. All rights reserved.)