The paper presents the evaluation of interleukin 6 (IL-6) and interleukin 6 soluble receptor (sIL-6R) values in the blood serum of patients with various forms of periodontitis (P), as confronted with local state. The study involved a group of 15 patients with P, including 4 patients with rapidly progressive periodontitis (RPP), 10 with adult periodontitis (AP) and 1 with juvenile periodontitis (JP). The concentration of IL-6 and its soluble receptor in blood serum were assessed using the immunoenzymatic ELISA method. The clinical state was estimated with the following periodontal indices: plaque index (PI), oral hygiene index (OHI), sulcus bleeding index (SBI), probing pocket depth and probing attachment loss. The P group showed an insignificant decrease in the IL-6 level in serum and a significant increase in sIL-6R concentration, compared with controls. A correlation was found between the level of IL-6 and PI, OHI and SBI.