The pair distribution function of the particles in a noncolloidal suspension was for the first time measured experimentally. Evidence of anisotropy in dilute suspensions of solid spheres is presented. Suspensions of polystyrene spheres in silicone oils with volume fractions0.01⩽c⩽0.05were subjected to cylindrical Couette flow in a Weissenberg Rheogoniometer. The experimental conditions were such that the Reynolds number based on the particle radius was very small,O(10−7)and the particle Péclet number very large,O(105),so that inertial effects and Brownian motion were negligible relative to viscous effects. Suspended spheres on a plane perpendicular to the axis of rotation were observed using a video camera interfaced with a VICOM image processing computer. Using automatic data gathering and processing techniques specially developed for this purpose, an analysis of the relative positions of the spheres showed that (under shear) the spheres were not uniformly distributed in the suspension, but rather were arranged anisotropically. Specifically, the probability of finding a sphere at a given location relative to a reference particle was found to be a maximum when the spheres were nearly touching and the line joining their centers was parallel to the direction of undisturbed flow. The experimental phenomena observed are consistent with the nature of two‐body hydrodynamic interactions between spheres.