An efficient method for calculating optimum dimensions of Cassegrain telescope baffles will be dis-cussed. The baffles are designed to prevent light which has bypassed the optical system or which is outside the field of view from reaching the final image plane. It is also desired to minimize the baffle size to maximize the effective aperture. Graphical methods have been used, but they are time consuming and have limited accuracy. Previous analytical techniques have been cumbersome and difficult to implement. The new technique presented here is an iterative algorithm suitable for implementation on a small computer. The authors have written such a program and have found it to give fast, reliable design information.