The influence of vitamin B6 deficiency on some vitamin D-dependent processes was studied in animals. The following parameters changing in relation to the level of vitamin D providing were investigated: activity of alkaline phosphatase in the serum and small intestine mucosa, the levels of Ca, P and parathormone, concentration of vitamin D metabolites and enzyme activity; and only 25-hydroxyvitamin D (25-OVD) concentration in the blood serum, under conditions of combined vitamin B6 and D deficiency was significantly lower as compared to cases with vitamin D deficiency alone. In the presence of vitamin B6 deficiency recovery of 25-OVD level in the blood serum, after vitamin D administration to the animals, had a tendency to delay as compared to that in the animals provided with vitamin B6. Vitamin B6 deficiency produced similar effect on 25-OVD 1-hydroxylase activity. The data obtained have evidenced a possibility of vitamin B6 influence on vitamin D metabolism.