During preoperative blood coagulation testing the factor VII (FVII) deficiency was found in two patients. No liver disease or cardiac insufficiency was found. No history of bleeding episodes existed. The latent (mild) deficiency of the FVII was diagnosed. The treatment with vitamin K (Vitacon) was administered in order to exclude vitamin K deficiency. The treatment showed no impact on the level of the FVII. Mixing study corrected the deficit (normal PT was found). Both patients underwent cardiac surgery with extracorporeal circulation. The epsilon-aminocapronic acid and fresh frozen plasma were used to prevent bleeding. The postoperative bleeding was compared to average of the year. No difference was found. The patients with mild FVII deficiency may safely undergo cardiac surgery with extracorporeal circulation.