The NCCN-International Prognostic Index (IPI) is reported to be more powerful than the former IPI for predicting survival in the rituximab era. To evaluate the NCCN-IPI in our institutions, we analyzed 188 patients with diffuse large B-cell lymphoma treated with rituximab plus CHOP or THP-COP chemotherapy. The 5-year overall survival rates of patients with low, low-intermediate, high-intermediate, and high risk were 90%, 76%, 64%, and 34%, respectively. Although there was no difference in overall survival between patients 61-75 and those >75 years of age, the NCCN-IPI is useful for classifying prognostically relevant subgroups of Japanese patients.