The longitudinal, rho parallel to, and transverse, rho perpendicular to, resistivities have been measured in Sb-InSb eutectic alloys unidirectionally solidified over a range of growth rates, 1.2 x 10(-4) to 1.2 x 10(-1) cm s(-1). The measured resistivities differ from the theoretical values estimated on the basis of macroscopic geometrical approximation for the spatial arrangement of Sb rods within the InSb matrix. The difference between the two is explained in terms of the contribution of the interface phase, as well as the loss of microstructural anisotropy. In the present work the interface between the Sb rod and the InSb matrix was regarded as a definite phase constituting an in situ eutectic composite. The presence of this interfacial phase was assumed to result in an increase of rho perpendicular to. The deg ree of microstructural anisotropy, delta, is defined from the geometrical relation determined by the rho parallel to value, allowing quantitative description of microstructural anisotropy. As expected, delta gradually decreases with increasing growth rate. Some of the quickly grown specimens have revealed radial directionality in their microstructure, which is reflected by the relative size of rho parallel to and rho perpendicular to values.