The aim of this retrospective study is to determine the efficacy, outcome and feasibility of standard CHOP regimen as a first line treatment to DLBCL using clinical risk stratification models such as International prognostic index (IPI) , patients profile and dose intensity of cyclophosphamide and adriamycin as effective tools for predicting outcome of the patients with lymphoma.The study includes two hundreds and twenty four patients with diffuse large B cell lymphoma who were treated with 3 to 8 cycles standard CHOP regimen during the period between 1998 and 2006. One hundred and seventy eight patients (79.5%) achieved CR after CHOP regimen with an observation period of 51 months.