Vessel calcification is a recognised cardiovascular morbidity risk factor in patients with chronic kidney disease (CKD). Recent reports indicate a significant role of Matrix Gla-protein (MGP) in decreasing calcification processes. MGP is excretion protein whose mechanism of action is not yet fully explained and which to be activated requires phosphorylation and carboxylation where cofactor is vitamin K. These observations indicate that shortage of vitamin K is a significant risk factor for the development of vessel calcification. Another calcification risk factor in CKD patients are calcium-phosphate disturbances and insufficiency of vitamin D3 which in physiological concentration stimulates MGP transcription. The aim of this study is estimation of influence of vitamin K2 administration over the period of 9 months on vessel calcification in 3.- 5. stage CKD patients.