Background: Increased risk of myocardial infarction (MI) and cerebrovascular accident (CVA) among NHL survivors is commonly attributed to NHL treatment. The extent to which pre-existing CV risk factors also contribute to increased risk is unknown. We investigated this association among an entire national population of NHL survivors who have a full range of important CV risk factors. Methods: Using Danish population-based registries, we identified all adults diagnosed with primary aggressive NHL from 2000-2010 and followed them for MI and CVA from 9 months after diagnosis through 2012. MI and CVA diagnoses were ascertained from the nationwide Hospital Discharge Register and Cause of Death Register. CV risk factors (hypertension, dyslipidemia, and diabetes), vascular disease, and intrinsic heart disease prevalent at NHL diagnosis were ascertained algorithmically using the National Prescription Register and the Hospital Discharge Register. Cumulative anthracycline dose was coded continuously. Receipt of radiation was coded dichotomously for both chest and neck. Controlling for age, sex, treatment, and CV diseases, we used Cox multivariate regression to test the association between pre-existing CV risk factors and subsequent CVA or MI. Results: Among 2604 patients with NHL, median age was 62, and median follow-up time was 2.4 years. Overall, 131 patients were diagnosed with MI or CVA. Before NHL diagnosis, 40% of patients had at ≥1 CV risk factor, 13% had vascular disease, and 6% had intrinsic heart disease. 90% of the patients were treated with anthracyclines, 9% had received chest radiation, and 15% had received neck radiation. Patients with ≥1 CV risk factor had an increased risk of MI or CVA compared to patients with none (HR = 1.5 [95% CI = 1.1-2.2). Prevalent vascular disease, prevalent intrinsic heart disease, and NHL treatment were not associated with MI or CVA (p’s > 0.05). Conclusions: In a large, well-characterized, and nationally representative cohort of NHL survivors, prevalent CV risk factors were associated with later CVA and MI. To prevent MI and CVA among survivors, decisions about post-treatment monitoring should take into account prevalent CV risk.