Chimeric antigen receptor-modified T (CAR T) cells are profoundly changing the standard of care in B-cell malignancies. This new therapeutic class induces a significant number of acute neurotoxicity, but data regarding mid- and long-term neurological safety are scarce. We evaluated mid-term neurological safety, with special emphasis on cognitive functions, in a series of adults treated with CAR T cells. Methods Patients treated in a single center with CD19-targeted CAR T cells for a relapsing B-cell lymphoma were prospectively followed up by neurologists. Before CAR T-cell infusion, all patients underwent neurological examinations with neuropsychological testing and filled out questionnaires assessing anxiety, depression, and cognitive complaints. Patients surviving without tumor progression were re-evaluated similarly, 6-12 months later. Results In this prospective cohort of 56 consecutive adult patients treated with CAR T cells, 27 were eligible for mid-term evaluation (median time 7.6 months). Twelve patients developed an acute and reversible neurotoxicity with median duration time of 5.5 days. In all patients, neurological examination on mid-term evaluation was similar to baseline. In self-assessment questionnaires, 63% of patients reported clinically meaningful anxiety, depression, or cognitive difficulties at baseline, a number reduced to 44% at the time of mid-term evaluation. On cognitive assessments, no significant deterioration was found when compared to baseline, in any cognitive functions assessed (verbal and visual memory, executive functions, language, and praxis), even in patients who developed acute neurotoxicity. Conclusion In this cohort of patients treated with CD19-targeted CAR T cells, we found no evidence for neurological or cognitive toxicity, 6-12 months after treatment.