Background The implementation of preventive therapies among patients with stroke remains inadequately explored, especially when compared with patients with myocardial infarction (MI), despite sharing similar vascular risk profiles. We tested the hypothesis that participants with a history of stroke have a worse cardiovascular prevention profile in comparison to participants with MI. Methods and Results In cross‐sectional analyses within the UK Biobank and All of Us Research Program, involving 14 760 (9193 strokes, 5567 MIs) and 7315 (2948 strokes, 4367 MIs) participants, respectively, we evaluated cardiovascular prevention profiles assessing low‐density lipoprotein (<100 mg/dL), blood pressure (systolic, <140 mm Hg; and diastolic, <90 mm Hg), statin and antiplatelet use, and a cardiovascular prevention score that required meeting at least 3 of these criteria. The results revealed that, within the UK Biobank, patients with stroke had significantly lower odds of meeting all the preventive criteria compared with patients with MI: low‐density lipoprotein control (odds ratio [OR], 0.73 [95% CI, 0.68–0.78]; P <0.001), blood pressure control (OR, 0.63 [95% CI, 0.59–0.68]; P <0.001), statin use (OR, 0.45 [95% CI, 0.42–0.48]; P <0.001), antiplatelet therapy use (OR, 0.30 [95% CI, 0.27–0.32]; P <0.001), and cardiovascular prevention score (OR, 0.42 [95% CI, 0.39–0.45]; P <0.001). Similar patterns were observed in the All of Us Research Program, with significant differences across all comparisons ( P <0.05), and further analysis suggested that the odds of having a good cardiovascular prevention score were influenced by race and ethnicity as well as neighborhood deprivation levels (interaction P <0.05 in both cases). Conclusions In 2 independent national cohorts, patients with stroke showed poorer cardiovascular prevention profiles and lower adherence to guideline‐directed therapies compared with patients with MI. These findings underscore the need to explore the reasons behind the underuse of secondary prevention in vulnerable stroke survivors.