There is now some evidence that major depression is accompanied by an immune response with an increased production of pro-inflammatory cytokines. The aim of the present study was to examine serum level of cytokines: interleukin-6 (IL-6), which is considered pro-inflammatory one and anti-inflammatory cytokines: interleukin 10 (IL-10), and interleukin-1 receptor antagonist (IL-1Ra) in acute clinical state of depression and after 6-week antidepressant treatment. Serum IL-6, IL-10, IL-1Ra levels were higher in the subjects with major depression than in normal controls although these results were not statistically significant. The mean score according to the Hamilton Depression Rating Scale (HDRS) in the patients significantly decreased during the 6 weeks of the study, demonstrating an overall improvement. Successful antidepressant treatment had no significant effect on serum level of this cytokines.