The linear stability of steady circular Couette flow with a small radial temperature gradient has been investigated. The outer cylinder is assumed stationary, while the inner cylinder is rotated with a constant angular speed. The interaction of the radial temperature gradient with both gravity and centrifugal potentials is taken into account in the formulation of the stability problem. The critical Reynolds number is found to be dependent on the ratio of the centrifugal and gravitational potentials, the Prandtl number, and the temperature difference between the cylinders. Unlike previous theoretical results, the present results agree qualitatively with those obtained experimentally.