The purpose of this study was to assess the prognostic value of a large panel of cytokines in aggressive non-Hodgkin's lymphoma (NHL) and to confront it to parameters of the International Prognostic Index (IPI). It investigated the concomitant determination of interleukin-2 (IL-2), soluble interleukin-2 receptor (sIL-2R), interleukin-4 (IL-4), interleukin-6 (IL-6) and interleukin-10 (IL-10) on a uniform population of 116 previously untreated patients. Commercially available enzyme-linked immunoassay kits were used for cytokines measurements. Results were correlated with complete remission (CR), overall survival (OS) and failure free survival (FFS). In univariate analysis, sIL-2R and IL-6 demonstrated prognostic significance for CR (p = 0.016 and p = 0.048), OS (p = 0.0011 and p = 0.0387) and FFS (p = 0.0001 and p = 0.0363), but multi-variate analysis failed to demonstrate an independent prognostic significance. In the intermediate group risk defined by IPI, patients presenting high level of sIL-2R or IL-6 demonstrated lower CR rate and survival than those with low level. In conclusion, sIL-2R and IL-6 serum levels are elevated in high grade NHL and are correlated to CR, OS and FFS, but this study did not support their independent prognostic value. However, sIL-2R and IL-6 measurements may improve risk assignment by IPI and allow a better prognostic evaluation of patients with intermediate prognosis NHL.