Involvement of the cytokines in male infertility were considered from in vitro studies, however the nature and the role of the mediator susceptible of arising in vivo is not completely elucidated. The purpose of this study is to measure the concentrations of interleukin-2 (IL-2) in normal and pathologic seminal fluid and to analyse their relationship with semen parameters. Our results demonstrate the presence of IL-2 in seminal fluid. Comparatively to normal seminal fluid, significant lower IL-2 concentrations were observed in infected semen samples or with sperm antibodies. No correlation was found between the cytokines values and the sperm parameters.