The cerebral blood flow, CBF, is an important clinical parameter in neuro-intensive care. The possibility to continuously monitor CBF, computed from referential ICP (rICP, calculated from measured ICP and mean CVP) and venous outflow resistance, Rv, could importantly improve patient care. The theoretical background involves rICP (the venous perfusion pressure) and the pulsative part of CBF (with rICP increase due to vascular volume increase) which gives the venous outflow resistance, Rv. rICP divided with Rv then gives CBF. The parameters rICP, Rv and CBF were then calculated in the same way in nine subjects from measurements of ICP and of intracerebral venous volume increase. The result was two methods for continuous monitoring of CBF from rICP, one using the systolic ICP increase, and one using the relationship between Rv and rICP at rICP exceeding about 10 mmHg, The constant monitoring of rICP opens the possibility to constantly monitor CBF and other clinical parameters, like venous outflow resistance, and mean arteriolar sphincter resistance.