 This multicenter, observational study will evaluate the correlation between clinical and biological factors and International Prognostic Index IPI as prognostic factors in patients with diffuse large B-cell lymphoma receiving first-line treatment with MabTheraRituxan rituximab in combination with CHOP chemotherapy. Eligible patients receiving treatment according to standard of care and local guidelines will be followed for the duration of treatment approximately 8 months and during 1 year of follow-up. 