There is the prevalence of the genes CYP2C9 and VKORC1 in patients with prosthetic heart valves in the Kemerovo region. According to this it was formed two groups of patients with no statistically significant differences in genetic, clinical and anthropometric data. The groups were formed by using method of "copy-pair". In the first group traditionally warfarin was administered 5 mg/day with subsequent dose adjustments under the control of international normalized ratio (INR). In the second group the initial and therapeutic doses of warfarin were selected individually by using the programme available on the site www.warfarindosing.org. It was revealed that the use of pharmacogenetic testing of sensitivity to warfarin reduces 2 times terms of dose selection in the early postoperative period in these patients. Also this method reduces multiplicity of INR control. The first test is made on the third day of treatment, and then there is daily monitoring for obtainment of the desired level of anticoagulation. In the future the control is made every 2-3 days.