AbstractCD19-targeted chimeric antigen receptor (CAR) T cell therapy is an effective treatment for diffuse large B cell lymphoma (DLBCL). In addition to cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity (ICANS), B cell aplasia and hypogammaglobulinemia are common toxicities predisposing these patients to infections. We analyzed 60 patients with DLBCL treated with FDA-approved CD19 CAR T cells and report the incidence, risk factors, and management of infections during the first year after treatment. A total of 101 infectious events were observed, including 25 mild, 51 moderate, 23 severe, 1 life-threatening, and 1 fatal infection. Bacteria were the most common causative pathogens. The cumulative incidence of overall, bacterial, severe bacterial, viral, and fungal infection at 1 year were 63.3%, 57.2%, 29.6%, 44.7%, and 4%, respectively. In multivariate analyses, the use of systemic corticosteroids for the management of CRS or ICANS was associated with an increased risk of infections and prolonged admission. Impaired performance status and history of infections within 30 days before CAR T cell therapy was a risk factor for severe bacterial infection. In conclusion, infections were common within the first 60 days after CAR T cell therapy, however, they were not associated with an increased risk of death.