Purpose <p>We aimed to evaluate the prognostic value of pre- and post-infusion ¹⁸F-FDG PET/CT for B-cell non-Hodgkin lymphoma B-NHL) patients treated with anti-CD19 chimeric antigen receptor T (CAR-T) cells.</p> Methods <p>B-NHL patients who received CAR-T therapy and underwent ¹⁸F-FDG PET/CT examination one month before (pre-infusion) and after (M1) CAR-T infusion were collected and regularly followed up. Maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV), total lesion glycolysis (TLG) was recorded for each PET/CT performed, as well as some clinical and laboratory indexes. Progression-free survival (PFS) and overall survival (OS) were endpoints, estimated by the Kaplan-Meier method.</p> Results <p>Ninety-three patients were included. The median follow-up time was 21.1 months. Multivariate analysis showed that extranodal (EN) sites and SUVmax at M1 were independent prognostic factors for PFS. Patients with EN sites ≥ 2 had shorter median PFS than those with EN sites &lt; 2 (6.4 months vs. not reached [NR], <i>P</i> = 0.032). Patients with M1 SUVmax ≥ 12.4 had shorter median PFS than those with SUVmax &lt; 12.4 (1.1 months vs. NR, <i>P</i> &lt; 0.001). Regarding OS, International Prognostic Index (IPI) and SUVmax at M1 were strongly associated with subsequent outcomes. The median OS was 14.1 months for patients with IPI ≥ 3, compared with NR for those with IPI &lt; 3 (<i>P</i> = 0.011). Patients with SUVmax &lt; 12.9 at M1 had longer median OS compared to those with SUVmax ≥ 12.9 (NR vs. 12.0 months, <i>P</i> &lt; 0.001).</p> Conclusion <p>For B-NHL patients who received CAR-T therapy, M1 PET/CT had a more important prognostic value than the pre-infusion one. EN sites and SUVmax at M1 were independent risk factors for PFS, and IPI and SUVmax at M1 for OS. Integrating the clinical characteristics and PET/CT parameters can be helpful for early decision-making in patient management.</p> Clinical trial number <p>Not applicable.</p>