Abstract Background: Cardiovascular disease (CVD) is a major cause of morbidity and mortality among men diagnosed with prostate cancer. We evaluated the extent to which men with prostate cancer develop CVD accounting for potential factors that may contribute to the CVD burden in this population. Methods: We prospectively followed men diagnosed with prostate cancer and free from CVD (stroke and coronary heart disease, including myocardial infarction, coronary artery bypass graft, and percutaneous coronary intervention) before their cancer diagnosis in the Health Professionals Follow-up Study, between 1986 and 2016. Men were categorized by D’Amico prostate cancer risk groups as low-risk (stage T1-2a, Gleason score ≤6, and PSA at diagnosis ≤10 ng/mL), intermediate-risk (T2b and/or Gleason score 7 and/or PSA >10-20), or high-risk (≥T2c/N1/M1 or Gleason score 8-10 or PSA >20). Incident fatal and non-fatal CVD, defined as coronary heart disease and stroke after cancer diagnosis, were centrally adjudicated. CVD risk factors including smoking, hyperlipidemia, hypertension, diabetes mellitus, body mass index, were self-reported on biennial questionnaires. Deaths due to prostate cancer or other causes were treated as competing events when estimating cumulative incidence and cause-specific hazard ratios (HR). Results: Among 5,707 prostate cancer patients, 1,912 had low-risk, 2,261 had intermediate-risk, and 1,534 had high-risk cancer. 1,102 CVD events were documented over up to 30 years of follow-up after cancer diagnosis. The 10-year CVD risk was 8.1% for men with low-risk cancer, 8.8% for intermediate-risk, and 10.4% for high-risk cancer. The cause-specific HRs for CVD were 1.18 (95% CI 1.03, 1.36) in intermediate-risk and 1.59 (95% CI 1.36, 1.85) in high-risk prostate cancer, both compared to low-risk prostate cancer. Men with high-risk cancer tended to be older; after age adjustment, the HRs were 1.15 for intermediate-risk (95% CI 1.00, 1.33) and 1.35 for high-risk cancer (1.35, 95% CI 1.16, 1.58). Associations between cancer risk group and CVD were essentially unchanged after further adjustment for CVD risk factors present at cancer diagnosis, primary cancer treatment modality (surgery, radiation, androgen deprivation therapy, watchful waiting/active surveillance), and calendar year of diagnosis. Discussion: Despite the elevated risk of cancer mortality in men with intermediate-risk and high-risk prostate cancer compared to low-risk prostate cancer, CVD risk remains at least as common over time among these men as among men with low-risk prostate cancer. Incident CVD risk after cancer diagnosis among men with more aggressive cancers, which particularly occur in older men, is not primarily attributable to differences in pre-existing risk factor burden. These findings from a cohort with healthcare access and literacy indicate a need for continued clinical attention to CVD after cancer diagnosis. Citation Format: Caroline Himbert, Anna Plym, Jane B. Vaselkiv, Andreas Pettersson, Philip W. Kantoff, Lorelei A. Mucci, Kenneth J. Mukamal, Konrad H. Stosapck. Cardiovascular disease risk among men with prostate cancer: Differences by prostate cancer aggressiveness [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2234.