The present study reports results of a numerical investigation of natural convection in a spherical porous annulus. The inner and outer surfaces are subjected to constant temperatures. The Brinkman extended Darcy flow model is considered in this study. The problem has been solved numerically employing successive accelerated replacement scheme. The effect of parameters like Rayleigh number, Darcy number and radius ratio on the fluid flow and heat transfer has been examined. There exists a critical radius ratio at which the average Nusselt number attains a peak value. The average Nusselt number decreases as the Darcy number increases.