Introduction: Sexual and gender minority (SGM) individuals have higher prevalence of dementia risk factors compared to non-SGM individuals. However, it is not known if differences in cognitive function appear during midlife, as prior studies lack comprehensive measures for sex, sexual orientation, and gender identity (SSOGI) or standardized cognitive assessments. We utilized Coronary Artery Risk Development in Young Adults (CARDIA) study data to assess midlife cognition by SSOGI. Hypothesis: We hypothesize that middle-aged sexual minority (SM) and transgender and non-binary (TGNB) participants demonstrate worse cognitive test scores compared to non-SM and non-TGNB participants, respectively. Methods: A total of 1,978 CARDIA participants completed cognitive assessments at Y25 and self-reported SSOGI measures at Y35. Participants with a history of brain cancer, kidney failure, or stroke prior to Y25 were excluded. Y25 examination included administration of standardized cognitive assessments of verbal memory (Rey Auditory Verbal Learning Test; RAVLT), processing speed (Digit Symbol Substitution Test; DSST), and executive function (Stroop Test). SSOGI variables are listed in Table 1 . Wilcoxon t-tests were used to compare cognitive test scores between analytic subgroups. Results: Mean age of the overall cohort at Y25 was 45 (SD = 3.6) years and 43% identified as Black. TGNB individuals performed significantly worse on a memory recall portion of the RAVLT ( p <0.001) and DSST ( p <0.05) compared to non-TGNB individuals. There was no significant difference in cognitive test scores between SM and non-SM and gay/lesbian and bisexual individuals. See Table 1 for statistical results. Conclusions: Preliminary findings suggest TGNB individuals may demonstrate lower midlife cognitive performance related to verbal memory and processing speed compared to non-TGNB individuals. Future studies will analyze associations of depression and chronic conditions with cognitive scores and expand to later CARDIA time points.