Approximately 25-35% of patients with diffuse large B-cell lymphoma (DLBCL) are older than 70 years. The aim of this study was to investigate the prognostic impact of depletion of skeletal muscle (sarcopenia) in elderly patients with DLBCL. This retrospective analysis included 82 patients with DLBCL older than 70 years and treated with R-CHOP (rituximab, cyclophosphamide, doxorubicin, Oncovin, prednisone) or R-miniCHOP. Sarcopenia was measured by the analysis of stored computed tomography (CT) images at the L3 level at baseline. The surface of the muscular tissues was selected according to the CT Hounsfield unit. This value was normalized for stature in order to calculate the lumbar L3 skeletal muscle index (LSMI, in cm(2)/m(2)). The mean age of the population was 78 years. According to the defined cut-offs for LSMI, 45 patients with DLBCL were considered sarcopenic. Sarcopenic patients displayed a higher revised International Prognostic Index (R-IPI) compared with patients without sarcopenia, and were older, with a mean age of 80 years and 77 years, respectively (p = 0.006). With a median follow-up of 39 months, the 2-year overall survival in the sarcopenic population was 46% compared with 84% in the non-sarcopenic group (HR = 3.22; 95% CI = 1.73-5.98; p = 0.0002). In a multivariate analysis, sarcopenia remained predictive of outcome (p = 0.005). Sarcopenia is a relevant and predictive factor in elderly patients with DLBCL treated with rituximab plus chemotherapy.