Abstract Introduction. Non-Hodgkin's lymphoma (NHL) is the fifth most common cancer in the United States. B-cell lymphoma accounts for 80-90% of NHL cases. Younger age at cancer diagnosis is associated with higher survival rates. However, younger cancer survivors may experience accelerated aging due to the cancer treatment that they undergo. The aim of this population-based study is to estimate long-term cardiovascular risk among younger and older adult NHL survivors compared to their respective general population cohorts. Methods. B-cell non-Hodgkin's lymphoma (B-NHL) survivors diagnosed from 1997 to 2015 in the Utah Cancer Registry were matched with up to five cancer-free individuals on birth year, sex, birth state, using the statewide Utah Population Database. Electronic medical records and statewide healthcare facility data were used to identify disease outcomes 5 years or more after cancer diagnosis. Cox Proportional Hazards models were used to estimate hazard ratios (HR). Test for heterogeneity was used to compare the HR for the older and younger cohorts. Results. There were 2,146 B-NHL survivors (1,284 diagnosed <65 years old and 862 diagnosed ≥65 years old) and 13,880 individuals from the general population ≥5 years after cancer diagnosis. Both younger and older B-NHL survivors had elevated risks for congestive heart failure, respectively (HRyounger = 1.65, 99% CI = 1.07-2.56; HRolder = 1.40, 99% CI = 1.01-1.96) compared to their respective general population cohorts. The younger B-NHL cohort had higher relative risks for chronic rheumatic disease of the heart valves (HRyounger = 2.87, 99% CI=1.64-5.02; HRolder=1.17, 99% CI=0.73-1.90; p-valueheterogeneity = 0.017), peri-; endo-; and myocarditis (HRyounger =2.26, 99%CI=1.34-3.79; HRolder = 0.80, 99% CI=0.46-1.39; p-value heterogeneity = 0.007), and cardiomyopathy (HRyounger=2.14, 99%CI=1.18-3.91; HRolder=0.93, 99%CI=0.51-1.72; p-valueheterogeneity= 0.056) than the older cohort. For other CVD outcomes, increased risks were observed in the younger B-NHL survivors and not in the older B-NHL survivors, but these differences were not statistically significant. Smoking and baseline obesity were major long-term risk factors of heart disease among younger B-NHL survivors. First course cancer treatment was not associated with cardiovascular disease risks ≥5 years after cancer diagnosis among B-NHL survivors. Conclusion. Elevated long-term risk for congestive heart failure was observed in B-NHL survivors compared to the general population. Younger B-NHL survivors had higher relative risks than older B-NHL survivors for chronic rheumatic heart disease, peri-; endo-; and myocarditis, and cardiomyopathy compared to their respective general population cohort groups. Although these increased disease risks suggest some early aging for young B-NHL survivors, most cardiovascular disease risks were not different between the two age groups. Citation Format: Krista Ocier, Sarah Abdelaziz, Seungmin Kim, Kerry Rowe, John Snyder, Vikrant Deshmukh, Michael Newman, Alison Fraser, Ken Smith, Kimberly Herget, Christy Porucznik, Kimberley Shoaf, Joseph Stanford, Catherine Lee, Mia Hashibe. Cardiovascular disease risks in younger and older B-cell non-Hodgkin's lymphoma survivors [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 5803.