Most data on overall survival (OS) and adverse events (AEs) in patients with mantle cell lymphoma (MCL) are from controlled trials; therefore, in this population-based study, we retrospectively assessed treatment patterns, OS, and AEs in MCL patients initiating systemic treatment during 2013-2015 using the United States Medicare claims database. Among 1390 eligible patients (median age = 74 years), chemoimmunotherapy with bendamustine/rituximab (BR) was the preferred choice in first-line (35.3%), followed by ibrutinib (33.5%), rituximab (9.1%), and rituximab/cyclophosphamide/doxorubicin/vincristine (R-CHOP) (6.8%). Twenty-four-month OS was 73% for BR; 47%, ibrutinib; 72%, rituximab; and 71%, R-CHOP. For the four most commonly used regimens, neutropenia, anemia, hypertension, and infection were the most frequent AEs. Patients with ≥3 AEs had nearly four times higher monthly costs than those with 0-2 AEs in the first observed therapy line. Findings demonstrate a substantial increase in the economic burden as the number of AEs increased among the Medicare MCL patients.