Introduction: The achievement of a clinical response to the first induction chemotherapy has been considered for predicting survival in patients (pts) with aggressive non-Hodgkin lymphoma (NHL). Reduced dose intensity of chemotherapy has been likely to compromise long-term outcome of the patients with aggressive NHL treated with a standard chemotherapy of cyclophosphamide (CY), doxorubicin (ADR), vincristine and prednisone (CHOP). In particular, recent studies have revealed the relevance of relative dose intensity (RDI) to clinical outcomes, with reduced RDI leading to a poor survival, as well as the impact of RDI Methods: Data were retrospectively collected on 100 pts with DLCL who had been initially treated with more than 3 courses of CHOP (n=70) or CHOP plus rituximab (CHOP-R, n=30) at our institution between 1995 and 2006. We evaluated whether RDI might affect clinical outcomes, including complete response (CR) and event free survival (EFS). The average RDI derived from CY and ADR (referred to as RDI-CY/ADR) was determined for each patient, with classified into 2 populations according to the differences from the value of 85%, including RDI-CY/ADR Results: The median age of the study population was 54 years (range, 17 to 76), with 36 pts older than 60 years (yrs) of age. According to International Prognostic Index (IPI) score, pts were classified into 2 groups of low/ low-intermediate (n=46) and high/ high-intermediate (n=54). The overall CR rate reached 62%, and the probability of overall survival (OS) or EFS at 5 years estimated 77% or 43%, respectively with a median follow-up of 13.3 months. Multivariate analysis identified RDI-CY/ADR Conclusion: These data thus suggested the impact of RDI-CY/ADR