Fas (CD95/APO-1) is a protein that is mainly related to apoptosis of lymphoid cells. The increment of Fas expression is associated with long-term survival in various malignancies. However, there are limited studies regarding the effect of Fas expression on the course and prognosis of non-Hodgkin's lymphoma. The aim of this study was to investigate the significance of immunohistochemical Fas expression on the prognosis of nodal diffuse large B-cell lymphoma. A total of 63 patients with primary nodal diffuse large B-cell lymphoma diagnosed in the Erciyes University Department of Hematology between 1990 and 2003 were included in the study. The median age of the patients was 55 years old (range 19-102 years old). The median follow-up period was 19 months (2-132 months). Histopathological sections were stained immunohistochemically and evaluated by light microscopy for Fas, bcl-2, and p53. Clinical and laboratory parameters including Fas, bcl-2, and p53 positivity, age, sex, performance status, clinical stage, presence of B symptoms, bone marrow involvement, extranodal involvement, and lactic dehydrogenase levels were evaluated to compare overall survival. Complete remission was obtained in 28 patients (44.4%) after first-line chemotherapy. Fas positivity, male gender, good performance status, clinical stage I-II, absence of B symptoms, normal lactic dehydrogenase value, and absence of bone marrow involvement were favorable prognostic factors for complete remission in statistical analysis. Multivariate analysis revealed that positive Fas expression and ECOG performance status were independent prognostic factors for overall survival. Also, Fas-positive patients had significantly prolonged progression-free survival. Immunohistochemical Fas positivity was a favorable prognostic factor for complete remission and overall and progression-free survival in primary nodal diffuse large B-cell lymphoma.