The conductivity of stationary and flowing blood was measured at different hematocrit values (H). For stationary blood with erythrocytes in random orientation, the conductivity in S/m is estimated to be 1.57/[1+CH/(1-H)], with C=1.91. Variations in orientation cause C to vary between 1.18 and 3.35. The relative percent change conductivity for laminar flow in a circular tube with constant flow rate is also given. The estimate of the conductivity with parallel orientation for stationary blood and flowing blood are shown to be in good agreement