The preparation of long bar specimens of single crystals of close-packed hexagonal cobalt, about 10 cm long, was succeeded for the first time by the present authors, and with these crystals, the anisotropy of electrical resistivity and the magneto-resistance effect were measured up to the field of 1000 Oe. It was found that the specific electrical resistivity was largest in the direction of c-axis and smallest in the direction perpendicular to the axis, being 10.280×10^Ω-cm and 5.544×10^Ω-cm, respectively, and the values of ΔR/R were about 0.4 per cent and about 0.2 per cent the respective directions
