Abstract The emergence of chimeric antigen receptor (CAR) T-cell therapy has changed the treatment landscape for diffuse large B-cell lymphoma (DLBCL); however, real-world experience reporting outcomes among older patients treated with CAR T-cell therapy is limited. We leveraged the 100% Medicare fee-for-service claims database and analyzed outcomes and cost associated with CAR T-cell therapy in 551 older patients (aged ≥65 years) with DLBCL who received CAR T-cell therapy between 2018 and 2020. CAR T-cell therapy was used in third line and beyond in 19% of patients aged 65 to 69 years and 22% among those aged 70 to 74 years, compared with 13% of patients aged ≥75 years. Most patients received CAR T-cell therapy in an inpatient setting (83%), with an average length of stay of 21 days. The median event-free survival (EFS) following CAR T-cell therapy was 7.2 months. Patients aged ≥75 years had significantly shorter EFS compared with patients aged 65 to 69 and 70 to 74 years, with 12-month EFS estimates of 34%, 43%, and 52%, respectively (P = .002). The median overall survival was 17.1 months, and there was no significant difference by age groups. The median total health care cost during the 90-day follow-up was $352 572 and was similar across all age groups. CAR T-cell therapy was associated with favorable effectiveness, but the CAR T-cell therapy use in older patients was low, especially in patients aged ≥75 years, and this age group had a lower rate of EFS, which illustrates the unmet need for more accessible, effective, and tolerable therapy in older patients, especially those aged ≥75 years.