The purpose of the study was to establish the diagnostic informative value of the concentration of osteomarkers in the serum to assess the severity of the osteodestructive component in chronic generalized periodontitis (HGP) prior to surgery and the prognosis of the effectiveness of surgical treatment of the disease. 187 patients with moderate and severe HGP who underwent bone and plastic insertion during the patch operations were examined. In the blood serum, the concentration of osteoprotegerin, ligand of the soluble activator of the kappa B nucleation factor (sRANKL) was initially determined and at 8 and 12 months after the operation, bone isoenzyme of alkaline phosphatase, osteocalcin, C-terminal telopeptides of degradation of mature type 1 collagen (β-CrossLaps). It was found that in assessing the severity of osteodestructive processes in the periodontium in HGP, the serum concentration of sRANKL and β-CrossLaps is informative. When the sRANKL content in the blood serum exceeds 0,48 pmol/l, and β-CrossLaps exceeds 0,795 ng/ml, it is possible to judge the high activity of osteoclasts, which is accompanied by a pronounced risk of irreversibility of the osteodestructive component and the lack of effectiveness of surgical treatment.