Aim. The aim of the study was to examine the activity of selected cytokines in bipolar patients during manic and depressive episodes and in remission. Method. The cytokine status was assessed in 76 bipolar patients, 35 with mania - and 41 with depression. For cytokine measurements blood samples were drawn from each patient twice - while in an acute episode and in remission. 78 healthy individuals were examined once. Serum samples were tested for concentrations of : IL-6, IL-10, IL-1 beta, TNF-alpha, IFN-gamma using the cytometric method. The patients' mental status was assessed with Young Mania Rating Scale and Hamilton Depression Rating Scale. Results. Concentration of IL-6 was higher during the manic state as compared to control group. Additionally, IL-6 level was higher in mania than in remission. Concentration of IL-10 was higher in patients in remission after manic episodes than in healthy controls. In manic patients raising of IFN-gamma level was accompanied by more severe symptoms evaluated with YMRS. In remission after mania there was a correlation between IL-6 concentration and the intensity of the manic state. IFN-gamma level was higher in depressed patients comparing to remission, as well as manic patients and subjects from control group. IFN-gamma in remission after depression was still higher than in the healthy controls. Concentration of IL-1 beta was higher in depressed patients comparing to healthy subjects. Conclusion. The results obtained in this study show disturbances of the immune system in bipolar patients. These disturbances have features of either decrease or pathological increase of the immune response. Cytokines' profiles were different for mania and depression. Clinical improvement seems to be connected with immunomodulation process that results in changes of cytokine levels in bipolar patients in remission.