Blood coagulation and fibrinolysis parameters were studied during 10 days of total fasting in healthy, normal weight males. A reduction of plasma levels of factor VIII activity with a concomitant decrease in factor VIII antigen was found, without other laboratory evidence for a disseminated intravascular coagulation. The effect of 10 days' starvation on blood coagulation appears to be small but the effect of more prolonged starvation might implicate impaired hemostasis.