The National Comprehensive Cancer Network (NCCN)-International Prognostic Index (IPI) and GELTAMO (Grupo Español de Linfomas/Trasplante Autólogo de Médula Ósea)-IPI were developed to enable better risk prediction of patients with diffuse large B-cell lymphoma (DLBCL). The present study compared the effectiveness of risk prediction between IPI, NCCN-IPI, and GELTAMO-IPI in patients with DLBCL particularly in terms of determining high-risk patients. Among 439 patients who were enrolled to a prospective DLBCL cohort treated with R-CHOP immunochemotherapy, risk groups were classified according to the three IPIs and the prognostic significance of individual IPI factors and IPI models were analyzed and compared. All three IPI effectively separated the analyzed patients into four risk groups according to overall survival (OS). Estimated 5-year OS of patients classified as high-risk according to the IPI was 45.7%, suggesting that the IPI is limited in the selection of patients who are expected to have a poor outcome. In contrast, the 5-year OS of patients stratified as high-risk according to NCCN- and GELTAMO-IPI was 31.4% and 21.9%, respectively. The results indicate that NCCN- and GELTAMO-IPI are better than the IPI in predicting patients with poor prognosis, suggesting the superiority of enhanced, next-generation IPIs for DLBCL.