The electrical resistivity of liquid Cu – Y alloys in the region of compositions 0-70 at.% yttrium at temperatures in the range 1200-1600 K is measured by means of a four-probe method. Intensive growth in the electrical resistivity of the melts is found with increasing yttrium concentration, with only weak temperature dependence of electrical resistivity. Percolation theory is applied to calculate the electrical conductivity of Cu – Y melts, taking into account thermodynamic data for ordered melts in an approximation to the associated solution model.