Diffuse large B-cell lymphoma is an aggressive type of lymphoma, potentially curable, with heterogeneous prognosis. The aim of this study was to determine prognostic significance of clinical, laboratory and immunohystochemical factors. The retrospective study was done in 50 patients with diffuse large B-cell lymphoma. The following parameters were investigated: demographic (age, sex), clinical (time to diagnosis, B symptoms, clinical stage), laboratory (erythrocyte sedimentarion rate, haemoglobin, lactate dehydrogenase, albumine), standard and revised international prognostic index, and immunohystochemical parameters, cluster designation 20, B-cell-2, and Ki67 expression. There were 20 females and 30 males, their average age being 54 (22-83) years. The majority of patients had advanced disease: B symptoms in 76%, III and IV stage in 78%, increased lactate dehydrogenase in 74%, high risk standard international prognostic index in 62% of patients. B-cell leukemia/lymphoma 2 expression was found in 57%, and high Ki67 in 62% of patients. Rituximab-Cyclophosphamnide, Hydroxydaunorubicin, Vincristine, Prednisolone and Rituximab-Cyclophosphamide, Hydroxydaunorubicin, Vincristine, Etoposide, Prednisolone were conducted in 72% (36), and Cyclophosphamide, Hydroxydaunorubicin, Vincristine, Prednisolone and Cyclophosphamide, Hydroxydaunorubicin, Vincristine, Prednisolone-like treatment in 28% (14) of patients. The complete remission rate was 74%, and the partial remission rate was 9%. A significant difference in survival was found between low intermediate and high intermediate S-IPI risk groups, good and bad risk R-IPI, and patients with complete remission and patients with other treatment responses. The other parameters, including Bcl-2 and Ki67 expression, and type of treatment did not show significant influence on survival. The expected five-year survival was 69%. Our results have shown that international prognostic index, and complete remission status have prognostic significance in diffuse large B-cell lymphomas.